Autism: a spectrum, dimensions or clusters? How about a multi-dimensional cluster of spectrums?

A write-up (see here) of the paper by Hyunsik Kim and colleagues [1] was the initial impetus for formulating this blog post, but it quickly escalated into something a little larger when the findings from Frank Duffy & Heidelise Als [2] also popped up.

The question at hand: how should one conceptualise autism? Is it truly a spectrum as per the Lorna Wing proposition, or is it something a trifle more complicated? As per the title of this post, should we perhaps be thinking about autism as some sort of "multi-dimensional cluster of spectrums?" I'll come back to that idea shortly.

Well, it's not for me to make definitive conclusions on this blog. Science rarely, if at all, provides an absolute 'truth' but rather the probability that something is approaching truth. Such a notion goes double when you consider the singular label of autism and the huge heterogeneity that it encompasses. There are no easy answers and probably little or no truths.

Starting with the Kim paper (including some notable names such as the surname 'Gadow') and the name of the research game was modelling, modelling in a computational sense. So: "The sample comprised 3,825 youth, who were consecutive referrals to a university developmental disabilities or child psychiatric outpatient clinic." The CASI-4R - formulated by Prof. Gadow - was the schedule administered, which includes "an ASD [autism spectrum disorder] symptom rating scale" among other things. Some nifty statistics were applied to the data and the initial findings were 'tested' on a further group of over 2500 children.

Results: "Based on comparison of 44 different models, results indicated that the ASD symptom phenotype is best conceptualized as multi-dimensional versus a categorical or categorical-dimensional hybrid construct." And the dimensions mentioned in that 'multi-dimensional' statement? Well, lucky for us they were something familiar: "social interaction, communication, and repetitive behaving."

Then to the Duffy/Als paper (again, these authors are no stranger to autism research) and a similar starting point: "The authors postulate that the broad definition of an omnibus 'spectrum disorder' may inhibit delineation of meaningful clinical correlations." Indeed, very familiar (see here). The conclusion: "evidence that an objectively defined, EEG [electroencephalogram] based brain measure may be helpful in illuminating the autism spectrum versus subgroups (clusters) question." The tool used by Duffy/Als in their study was something called NbClust "specifically designed to provide an objective means, i.e. independent of investigator choice, to identify the ‘optimal’ cluster number within a population." Said tool was applied to EEG data derived from 400 participants diagnosed with an ASD. Statistics and more statistics applied to the data revealed that: "430 subjects diagnosed as being on the autism “spectrum” and represented by 40 EEG coherence factors..., fell into two distinct clusters." These autism spectrum clusters differed from each other and importantly, from "554 subject neuro-typical control group subjects, not involved in the clustering process." Interesting results but an unfortunate use of the term 'neurotypical' (see here). Duffy & Als conclude that their data support a view whereby "autism disorder should not be seen as a continuous spectrum." So Kim & Duffy/Als arrive at similar conclusions: a singular 'spectrum' idea of autism is probably not the best way of conceptualising the essence of the label.

I would perhaps add in a little more evidence for the idea that 'multi-dimensional clusters of spectrums' is a potentially better fit. I used the words 'spectrums' (plural) because there is a growing body of evidence to support the idea of more than one 'type' of autism. I say that from the perspective of evidence for autism being 'acquired' under several different circumstances (e.g. accompanying inborn errors of metabolism, linked to exposure to certain infections or diseases, etc). There's also evidence that clinical profiles under the umbrella term autism are not uniform (e.g. regressive autism, the so-called 'optimal outcomers', differing developmental trajectories, etc). And when one looks at something like the success (or not) of intervention, it's plain to see that there is no universally shared genetics and/or biology of autism in the singular either (see here and see here for examples). Add in the idea that autism rarely appears in a diagnostic vacuum (see here) and that said comorbidity might 'cluster' in some subgroups of autism (see here), and I hope you can see why 'plural' might be a good addition to any attempt to re-conceptualise autism: spectrum, dimension, tapestry, cluster or however you think it should be defined...

Oh, and since we're on the topic of trying to conceptualise autism, a new book out recently has been reviewed in Nature (see here). It talks about how "conclusive findings about sex-linked brain differences have failed to materialize" which is particularly apt in relation to previous talk about 'extreme male brains' as a way of conceptualising [some] autism (see here). One quote I particularly liked from the review is this one: "The brain is no more gendered than the liver or kidneys or heart."

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[1] Kim H. et al. Quantifying the Optimal Structure of the Autism Phenotype: A Comprehensive Comparison of Dimensional, Categorical, and Hybrid Models. J Am Acad Child Adolesc Psychiatry. 2018 Oct 29. pii: S0890-8567(18)31894-X.

[2] Duffy FH. & Als H. Autism, spectrum or clusters? An EEG coherence study. BMC Neurol. 2019 Feb 14;19(1):27.

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"Starting this week, the first blood test for autism will be available to the public"

I have to say that of all the news outlets that I peruse now and again, the resource known as Disability Scoop is typically one of the best. They just always seem to be 'on the ball'. The headline titling this post - "Starting this week, the first blood test for autism will be available to the public" - comes from that resource and well, 'whoa' is a word that springs to mind.

The report details that a company called NeuroPointDX is "launching its NPDX AA test, a blood plasma test that screens for certain metabolic markers that the company has linked to autism spectrum disorder." Said test is based on some peer-reviewed science by Alan Smith [1] which concluded that the: "Identification and utilization of metabotypes of ASD [autism spectrum disorder] can lead to actionable metabolic tests that support early diagnosis and stratification for targeted therapeutic interventions." And before you ask, yes, I have covered the Smith paper before on this blog (see here).

Specific details of what is included in the NPDX AA test are, at the time of writing, not seemingly readily available. The 'AA' mention in the test name implies amino acids are going to be central to the analysis. Indeed, the Smith paper [1] talked about a few specific amino acids as potentially being important: "The combination of glutamine, glycine, and ornithine AADMs [Amino Acid Dysregulation Metabotypes] identified a dysregulation in AA/BCAA [branch chain amino acids] metabolism that is present in 16.7% of the CAMP [Children’s Autism Metabolome Project] ASD subjects and is detectable with a specificity of 96.3% and a PPV [positive predictive value] of 93.5%." What this translates into is that for at least one part of the very heterogeneous autism spectrum (maybe one or more of the autisms?), this test might be able to identify some metabolic issues that could be considered both diagnostic (for that particular 'type of autism') and also therapeutic, insofar as specific interventions aimed at specific amino acid 'issues' when identified (see here for one possible example).

Of course we've kinda been here before with the talk about a biological test for autism (see here for example) and history teaches us to be quite cautious when it comes to such discussions. We'll just have to see how well the NPDX AA test does 'in the field' before any further claims are made and even bigger 'shifts' in our knowledge of autism reported and accepted. But hey, at least give it a chance...

To close, your customary 'chat' from V to remember the date today...

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[1] Smith AM. et al. Amino acid dysregulation metabotypes: potential biomarkers for diagnosis and individualized treatment for subtypes of autism spectrum disorder. Biological Psychiatry. 2018. Sept 6

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The Children’s Autism Metabolome Project (CAMP) reports: "Amino acid dysregulation metabotypes"

The Children’s Autism Metabolome Project (CAMP), mentioned in the title of this post, is an initiative that aims to develop "a diagnostic blood test for autism." It's a project that grabbed my attention for a few reasons; not least the reliance on the science of metabolomics and the use of some pretty amazing technology headed under the term 'mass spectrometry' (see here for another example) to try and accomplish their goal.

The recent results published by Alan Smith and colleagues [1] provide some of the first results to come from the CAMP, and the observation that: "Identification and utilization of metabotypes of ASD [autism spectrum disorder] can lead to actionable metabolic tests that support early diagnosis and stratification for targeted therapeutic interventions." Just in case you were wondering: "A metabotype is a subpopulation defined by a common metabolic signature that can be differentiated from other members of the study population." Inevitable lay media headlines have also followed on from this work (see here).

The nuts and bolts? Well: "Dysregulation of AA metabolism was identified by comparing plasma metabolites from 516 children with ASD with those from 164 age-matched typically-developing (TYP) children recruited into CAMP." AA refers to amino acids, the biological building blocks of proteins, and how, yet again (see here and see here) these compounds might be quite important to at least some autism. Researchers were able to analyse blood (plasma) samples from the participants, pertinent to detecting various amino acids and looking at how levels might differ as a function of a diagnosis of autism. Interestingly and importantly, the words "Training and Test Sets" are also used in the Smith paper, denoting how: "A training set was used to identify metabotypes associated with ASD and a test set was used to evaluate the reproducibility of the metabotypes." Similar methodological processes have been noted in other autism metabolomic studies (see here). I'm not going to bore you with the technological details of the "Triple Quadrupole LC-MS/MS Method" used (I'm more inclined to q-ToF mass spec myself) but suffice to say that such technology did yield some pretty accurate and important results, and it wasn't all just about autism vs. not-autism either.

"A simple analysis of the mean concentrations of free plasma amines did not reveal meaningful differences between the ASD and TYP populations of children." This is an important point. It suggests that within this cohort, there was no significant difference in the biological profiles following a straight 'autism vs not-autism' analysis. Something perhaps not entirely unexpected given the significant heterogeneity under the behaviourally-defined label called autism. But... "scatterplots of amine levels indicated that there were subsets of children with ASD with amine levels at the extreme upper or lower end of the abundance distribution." Researchers then began zooming in on different sub-groups of their autistic cohort as part of their "Amino Acid Dysregulation Metabotype (AADM)" description. Such analysis revealed a few AADMs based on the ratios between various amino acids. Further: "Taken together, all AADMs identified an altered metabolic phenotype of imbalanced BCAA [branched chain amino acid] metabolism in 16.7% of CAMP ASD subjects with a specificity of 96.3% and PPV [positive predictive value] of 93.5%." This *could* be interpreted as suggesting that about 15% of kids with autism *could* be correctly identified via their amino acid profile.

Caveats? Well yes, a few. This was work, for example, based on a single blood sample from each participant, in effect, providing a snapshot of each person at a particular point in time. There are lots and lots of different variables that will affect our metabolome including health/illness, diet, exercise, any medicines taken, comorbidity, et al. It's not beyond the realms of possibility that any or all of those factors could have influenced the results both in the short- or longer-term. Indeed, I'd like to see a lot more research on the consistency of individual sample results across different time frames before any big claims about a diagnostic test for autism are made. Also, the term 'biomaker for autism': I again get the impression that there needs to be lots more 'cross-linking' discussion between groups committed to this research agenda (see here and see here for examples).

But I don't want to take anything away from this work and (hopefully) future publications to come the CAMP. And I do also want to mention a couple of other interesting snippets of information garnered from the current study. So, in one of the write-ups of the study, one of the authors who is not stranger to the concept of 'biomarkers for autism' (see here) discusses: "Amaral points to phenylketonuria (PKU) as a possible template. PKU is a rare disease in which the amino acid phenylalanine builds up, causing brain damage. However, relatively small dietary adjustments can make a big difference." PKU as a template for autism? I think I've heard that somewhere before (see here). And that's also to acknowledge that PKU and autism can very much exist together (see here) in the context that various inborn errors of metabolism seem to be able to produce autistic signs and symptoms (see here). And some of them are very treatable...

Also alongside, I must quickly mention about those branched-chain amino acids (BCAAs) highlighted by Smith et al. How, in the context of other previous important research talking for example, about a 'new form of autism found' (see here), there are lots and lots of research (and clinical) possibilities to come from the analysis of these types of amino acids in the context of autism (see here). And yes, this includes intervention...

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[1] Smith AM. et al. Amino acid dysregulation metabotypes: potential biomarkers for diagnosis and individualized treatment for subtypes of autism spectrum disorder. Biological Psychiatry. 2018. Sept 6.

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On biotin and 'some autism'

Although I've mentioned biotin (vitamin B7) in the context of autism before on this blog (see here), due credit needs to be given to Peter over at the Epiphany blog for more extensive coverage (peer-reviewed based) of this nutrient (see here). Discussing how, within the increasingly large range of conditions that manifest autism or autistic behaviour(s), there may be one or two 'types' of autism that manifest biotin deficiency, there is a pretty obvious course of intervention as and when deficiency is found: supplementation.

And supplementation is exactly what was discussed in the paper by Paul Benke and colleagues [1] reporting on a case report of a young female who presented with "features of autism spectrum disorder, isolated headaches, and episodes of headaches and limb shaking." Alongside those symptoms, authors also discussed a fairly unusual part of her clinical history where "hair and nails did not grow."

Although there are various reasons why hair and nails might not grow - indeed, just about every nutritional deficiency seems to affect something like nail health and growth - biotin was noted as a point of concern in this young lady's clinical picture. Indeed authors noted that: "Administration of biotin restored her nail and hair growth and improved intellectual ability and school performance." They added that use of acetazolamide, more typically indicated for glaucoma and/or epilepsy, seemed to provide some relief from other symptoms: "episodes of headaches, single limb shaking, and loss of consciousness." And before you say it, yes, autism is no protection against the development of headaches (see here).

Bearing in mind this was a single case report yet also acknowledging the tenet: 'if you've met one person, you've met one autistic person', I find descriptions such as this to often be revealing. Other case reports talking about biotinidase deficiency associated with autism [2], where biotinidase is the enzyme responsible for freeing up biotin bound to food (see here), add to the interest in this area. Specifically how some other symptoms - "seizures, weak muscle tone (hypotonia), breathing problems, hearing and vision loss, problems with movement and balance (ataxia), skin rashes, hair loss (alopecia), and a fungal infection called candidiasis" - associated with biotinidase deficiency are not a million miles away from what has been talked about in some autism literature too (see also the comments section of another post here).

As per my discussions on various other nutrients that seem to be 'deficient' in at least some people on the autism spectrum (see here and see here), the defining message seems to be that post-diagnosis of autism, a screening program needs to be put into place looking at various nutrients in the context of something like eating patterns and behaviours. This could be part of a broader range of screening for something like inborn errors of metabolism that can and do show a connection to some autism (see here) and often (always?) involve nutrients (see here for example). Or could just mirror what is happening in other parts of psychiatry, where physiological parameters are starting to gain some parity with behavioural/developmental/psychiatric ones (see here) mindful of what correcting any deficiency might bring to various aspects of health (see here)...

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[1] Benke PJ. et al. Biotin and Acetazolamide for Treatment of an Unusual Child With Autism Plus Lack of Nail and Hair Growth. Pediatr Neurol. 2018 Feb;79:61-64.

[2] Zaffanello M. et al. A case of partial biotinidase deficiency associated with autism. Child Neuropsychol. 2003 Sep;9(3):184-8.

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Autism and phenylketonuria: a double syndrome

I want to briefly talk about the letter to the editor from Esra Demirci [1] (open-access) today and a continuation of some rather important research/clinical chatter about the inborn error of metabolism called phenylketonuria (PKU) intersecting with cases of autism (see here).

The author describes a case report of a child who was diagnosed with an autism spectrum disorder (ASD) "after performing a clinical assessment that included the Autism Behavior Checklist (ABC) and Childhood Autism Rating Scale (CARS)" and then subsequently diagnosed with PKU following some important metabolic investigations. They also highlight how instigation of a low phenylalanine diet - the treatment of choice for PKU - seemed to impact on the presentation of autism: "Eight months after the phenylalanine intake diet was initiated, he began to make eye contact, look when his name was said, and form two word sentences. His ABC scores fell from 57 to 46, and his CARS scores fell from 48 to 42."

The 'double syndrome' mentioned in the title of this post refers to the idea that there may be those on the autism spectrum who also have "an already described medical condition" and findings of autism and PKU comorbid fall into that category. I have to say that I'm a fan of this kind of thinking given the range of particularly metabolic conditions that do see to have 'an autistic element' to them (see here for another example). Screening is yet again implied (bearing in mind that PKU is already fairly routinely examined in all newborns in many countries). The idea, also yet again, that use of a low phenylalanine diet might also affect some of the signs and symptoms of autism in such cases remains a point for further investigation into hows and whys...

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[1] Demirci E. Autism Spectrum Disorder and Phenylketonuria: Dyzygotic Twins with Double Syndrome. Noro Psikiyatr Ars. 2017 Mar;54(1):92-93.

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Demirci E (2017). Autism Spectrum Disorder and Phenylketonuria: Dyzygotic Twins with Double Syndrome. Noro psikiyatri arsivi, 54 (1), 92-93 PMID: 28566968

Presenting with the symptoms of autism and then diagnosed with phenylketonuria (PKU)

The case report from Betül Mazlum and colleagues [1] (open-access available here) illustrates once again that (a) the plural 'autisms' exist (see here) and (b) screening for inborn errors of metabolism (IEM) should be an important part of any autism assessment (see here). Indeed, screening for IEM should really be part of assessments for many different labels...

Detailing a case report wherein a 3-year old child came to clinical attention for "speech delay and social problems", the authors describe how following a diagnosis of "autism according to DSM-IV criteria" further investigations were undertaken. Said investigations included analysis of blood and urine amino acid levels and, voilà, high levels of phenylalanine were detected and a diagnosis of phenylketonuria (PKU) made. Initiation of a low phenylalanine diet (the treatment of choice for PKU) followed and was accompanied by some important [positive] changes to behaviour and cognition. Of particular note to the presentation of autism we are told that: "At 4 months follow-up improvement was noticed in his eye contact, joined attention and speech."

The authors further note: "This case was not at particular risk for PKU at first thought, being born to non-consanguineous parents and during a period when newborn screening with Guthrie test was widely applied in Turkey. Although the child had a heel prick in the hospital where he was delivered, the results are unavailable and therefore whether his sample was analyzed is questionable."

OK, this was a case report and whilst an important 'N=1' is not necessarily generalisable to all autism (or rather all autisms). Insofar as the methods talked about for establishing raised phenylalanine - "Blood and urine amino acid chromatography" - I would have liked to have seen a little more detail in relation to the specific 'chromatography' methods used and any results related to another aromatic amino acid (tyrosine). We don't also have any data on follow-up either (repeat biological testing)...

PKU is an important but quite rare IEM. This is not however the first time that PKU has been linked to autism or the presentation of autistic traits (see here) particularly in cases of 'untreated' PKU. Aside from PKU providing quite a good template for how diet - certain aspects of diet - can affect behaviour and mental state for some (see here) there are other potential implications and 'correlations' on the back of this work. Not least is the intersection between another intervention measure potentially indicated for PKU - tetrahydrobiopterin (sapropterin or BH4) - and research suggesting that the 'mopping up phenylalanine' properties of this compound might be potentially effective for some cases and facets of autism too (see here) based on double-blind, placebo-controlled trial results [2].

"The possibility of a metabolic disorder including PKU should be considered in any child presenting with symptoms of autism, learning or speech problems and PKU should be tested unless the newborn screening results are available." I wouldn't argue with those sentiments [3], allowing for the fact that other correlates should also be considered (see here for example) particularly it seems, when autism appears alongside something like intellectual (learning) disability. The question of whether the quite restrictive low phenylalanine diet typically indicated for PKU might also impact autistic signs and symptoms is something that science still perhaps needs to look into...

Music to close, and how about something lively from The King?

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[1] Mazlum B. et al. A late-diagnosed phenylketonuria case presenting with autism spectrum disorder in early childhood. Turk J Pediatr. 2016;58(3):318-322.

[2] Klaiman C. et al. Tetrahydrobiopterin as a treatment for autism spectrum disorders: a double-blind, placebo-controlled trial. J Child Adolesc Psychopharmacol. 2013 Jun;23(5):320-8.

[3] Bilder DA. et al. Neuropsychiatric comorbidities in adults with phenylketonuria: A retrospective cohort study. Mol Genet Metab. 2017 Mar 6. pii: S1096-7192(17)30052-5.

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Mazlum B, Anlar B, Kalkanoğlu-Sivri HS, Karlı-Oğuz K, Özusta Ş, & Ünal F (2016). A late-diagnosed phenylketonuria case presenting with autism spectrum disorder in early childhood. The Turkish journal of pediatrics, 58 (3), 318-322 PMID: 28266201

"New form of autism found"

"New form of autism found" went one of the headlines reporting on the paper by Dora C. Tărlungeanu and colleagues [1] and findings that "elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA [branched-chain amino acids] in human brain function." This work continues a rather important research story talking about how one 'type' of autism might have some important roots in relation to the branched-chain amino acids and their metabolism (see here and see here for more information).

So, mice were the focus on the paper by Tărlungeanu et al (including one Gaia Novarino on the authorship list) and an extension of the idea that the BCAAs may play an important role in some autism in these days of the plural 'autisms' (see here). SLC7A5 represents a gene that codes for a protein involved in the transport of BCAAs into the brain among other things. Researchers studied mice who were genetically 'edited' to present with a "deletion of Slc7a5 from the endothelial cells of the BBB [blood-brain barrier]." In effect, the area of the body where SLC7A5 serves those important transport duties, a hold-my-hand partner was missing resulting in lower brain levels of the BCAAS.

Researchers noted a few important things in those SLC7A5-missing mice; not least in relation to their mouse behaviour(s) and how bearing in mind mice are mice not people, they seemed to present with behavioural issues not a million miles away from that noted in relation to autism. 'Social interaction' was as I understand it, something potentially affected in those SLC7A5-missing mice. Further: "we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene" suggesting that their results might stretch to people too.

And then something else that might eventually be important: "we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice." Intracerebroventricular administration basically means an injection straight into the brain. After a few weeks of such injections, researchers noted that mouse behaviours began to change coincidental to the direct administration of those BCAAs.

This is interesting research. I know that not everyone on the autism spectrum presents with issues with the BCAAs (as far as we know). But in these days of increasing plurality when it comes to autism coupled to the rise and rise of study on the various inborn errors of metabolism in relation to autism (see here), this could be pertinent to at least one type of autism. I also appreciate that 'brain injections' of something like BCAAs are not exactly a desirable option for anyone so there is still some work to do in terms of how to correct any central BCAA deficiency if and when identified. Talk about a possible relationship between the BBB and autism in the Tărlungeanu paper also continues a theme (see here) where this important barrier separating the brain from the other contents of the body (and indeed, the outside world) might represent something potentially quite important to autism (see here) and indeed, with 'transporters' also in mind (see here).

Much more research is implied.

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[1] Tărlungeanu DC. et al. Impaired Amino Acid Transport at the Blood Brain Barrier Is a Cause of Autism Spectrum Disorder. Cell. 2016. Dec 1.

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Tărlungeanu, D., Deliu, E., Dotter, C., Kara, M., Janiesch, P., Scalise, M., Galluccio, M., Tesulov, M., Morelli, E., Sonmez, F., Bilguvar, K., Ohgaki, R., Kanai, Y., Johansen, A., Esharif, S., Ben-Omran, T., Topcu, M., Schlessinger, A., Indiveri, C., Duncan, K., Caglayan, A., Gunel, M., Gleeson, J., & Novarino, G. (2016). Impaired Amino Acid Transport at the Blood Brain Barrier Is a Cause of Autism Spectrum Disorder Cell, 167 (6), 1481-2147483647 DOI: 10.1016/j.cell.2016.11.013

Parent-mediated interventions for young children with autism meta-analysed

Do not mess with  Lois.

Today I'm posting on the topic of the paper by Rose Nevill and colleagues [1] concluding: "that while most outcome domains of parent-delivered intervention are associated with small effects, the quality of research is improving."

Parent-mediated interventions in relation to autism have been covered on this blog quite recently (see here) accompanied by that 'super-parenting' headline fail. Such approaches work on the idea that helping parents to "develop strategies for interaction and management of behaviour" [2] might be one route of early intervention when it comes to autism. The research road has however not been smooth when it comes to this class of intervention (see here) and despite some positives (see here) has perhaps not been the overwhelming success that many had hoped for.

Nevill and colleagues reviewed 19 trials of parent-mediated interventions for autism ("randomized clinical trials") looking at various outcomes in relation to core symptoms of autism and aspects such as communication and cognitive functions. The results kinda reiterate what we already know that so far, parent-mediated interventions aren't really cutting the statistical mustard when it comes to outcomes and important statistics related to effect sizes. Indeed, the [weighted] Hedge's g statistics produced by the authors on the cumulative data in this area can, at best, be described as 'modest' (and I mean at best). As a comparison, have a look at the Hedge's g stats produced by a meta-analysis of the placebo response when it came to autism [3]: "a moderate effect size for overall placebo response (Hedges' g=0.45, 95% confidence interval (0.34-0.56), P<0.001)" (based on "25 data sets (1315 participants)"). This bearing in mind that the parent-mediated intervention trials don't usually include a placebo condition (and indeed, typically don't even blind - how could you?)

I don't want to poo-poo all of this area of autism science because it may still be pretty important. A few things do however worry me about the attention here based on the ideas that parent-child interactions are somehow the be-all-and-end-all of autism (also harking back to the bad 'ole days) and that in these times of continued cost-savings and austerity, parents are being expected to carry out the same services as other professionals. On that first point focused on parent-child interactions, I've always been a little cautious about what this means. Certainly in light of the primary focus on this blog, looking at genetics, epigenetics and biochemistry when it comes to autism, parent-mediated interventions are to be seen as a reactive strategy attempting to deal with 'symptoms' not necessarily causes. Yes, I know 'symptoms' are what parents and other family members see and deal with day in day out, but I'm wondering how successful parent-mediated intervention would be if used in the context of autism secondary to an inborn error of metabolism for example? Surely it makes more sense to spend a little more time ruling out some of the potential reasons why autism or particular autistic features might come about (i.e. screening - see here and see here for some other examples) rather than universally providing a parent-mediated intervention manual and hoping for the best? I might also add that a greater recognition that among 'the autisms' (see here) there may be some important waxing and waning of presentation(s) (see here) potentially influenced by things like the presence of comorbidity too reiterates that every person is an individual and set manuals on parent-child interactions don't necessarily cover all that heterogeneity. And there's also the suggestion that some parent-mediated intervention options are also seemingly failing when it comes to important comorbidities such as anxiety (knowing how disabling these can be) as being something else that needs to be kept in mind.

We'll have to see how this area develops further but for now, I don't think anyone can seriously say the existing research on this topic has shown anything like the successes that everyone hoped for. And whilst we should celebrate the fact that "the quality of research is improving" I'm not sure one can blame the limited success of such an approach on previous poor quality research.

To close, today is a really, really big day for some of my brood who have their 1st Dan black belt grading. After several years of training, hard work and effort pertinent to their voyages through Shotokan karate it all comes down to examination this evening. Thanks and credit need to go to their Sensei for all their efforts in getting them this far, as well as a certain practitioner who is Shotokan YouTube royalty. Whoever you are, thank you.

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[1] Nevill RE. et al. Meta-analysis of parent-mediated interventions for young children with autism spectrum disorder. Autism. 2016. Nov 14.

[2] Oono IP. et al. Parent-mediated early intervention for young children with autism spectrum disorders (ASD). Cochrane Database Syst Rev. 2013 Apr 30;(4):CD009774.

[3] Masi A. et al. Predictors of placebo response in pharmacological and dietary supplement treatment trials in pediatric autism spectrum disorder: a meta-analysis. Transl Psychiatry. 2015 Sep 22;5:e640.

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Nevill, R., Lecavalier, L., & Stratis, E. (2016). Meta-analysis of parent-mediated interventions for young children with autism spectrum disorder Autism DOI: 10.1177/1362361316677838

Autism and inborn errors of metabolism

I'd like to think that the review article by Annik Simons and colleagues [1] (open-access) highlights some pretty strong evidence to suggest there being at least some connection between some autism and some of the collected inborn errors of metabolism. Indeed, when people generally talk about 'not knowing what causes autism' if we perhaps consider a more plural view of 'the autisms', there is a case to be made to say we might know what causes 'some' autism and some of it might lie in this area...

Inborn errors of metabolism (IEM) cover a whole host of different conditions "in which there is an accumulation of toxic and/or complex compounds or energy problems within the cells due to enzymatic defects or other protein dysfunction." The absolutely magnificent work of people like Robert Guthrie who's name is synonymous with the neonatal heel prick test offered to newborns to screen for various IEMs and a jobbing physician called Ivar Asbjørn Følling who lent his name to a condition that was eventually called phenylketonuria (PKU), have proved to be some of the real successes of modern medicine.

For quite a few years, peer-reviewed science has suggested some potentially important 'associations' between various behavioural and psychiatric labels manifesting in both treated and untreated IEMs (see here and see here for examples). Simons and colleagues decided to look through the collected research on this topic to provide "child and adolescent psychiatrists with an overview of metabolic disorders associated with child psychiatric symptoms, their main characteristics and recommendations for further investigations."

So after boiling down the available peer-reviewed literature to some 71 articles (and in so doing making an important distinction between an inborn error of metabolism and the 'metabolic syndrome'!) authors summarise some of the key IEM associated with labels such as autism, attention deficit hyperactivity disorder (ADHD), learning disability, psychosis and eating disorders. Given that (a) the paper is open-access and (b) this blog tends to favour autism research, I'm gonna focus in on some of the details pertinent to the autism spectrum. I do however recognise that when it comes to the term 'over-represented comorbidity' in autism some of the other diagnostic labels covered by Simons et al might also come into the frame.

Long quote coming up: "Known metabolic disorders in autism are phenylketonuria, disorders in purine metabolism (such as adenosine deaminase deficiency, adenylosuccinate lyase deficiency, dihydropyrimidine dehydrogenase and dihydropyrimidinase deficiencies), organic acidurias (such as propionic academia, 3-methylcrotonyl-CoA carboxylase deficiency and pyridoxine dependency), disorders of branched-chain amino acids creatine deficiency, biotinidase deficiency, cerebral folate deficiency, succinic semialdehyde dehydrogenase deficiency, Smith–Lemli–Opitz syndrome (SLOS), late infantile ceroid lipofuscinosis, histidinemia, Sanfilippo disease, glucose 6-phosphate dehydrogenase deficiency, urea cycle disorders, X-linked ichthyosis, and mitochondrial disorders." I've popped in a few links to other occasions where a specific IEM has been associated with autism and covered on this blog.

Simons and colleagues also cover some of the important research findings where specific amino acids have been analysed and found in unusual levels in cases of autism as potentially being important too. This is relevant because disordered amino acid levels as noted in the case of phenylketonuria (PKU) and the aromatic amino acids phenylalanine (and tyrosine) can be an important finding in relation to some IEM. That they specifically focus on some of the research looking at homocysteine levels and autism is rather interesting (see here) and something that I am going to be discussing in future posts.

What's more to say? Well, I think it is also important to highlight how Simons and colleagues talk about 'other signs and symptoms of the metabolic disease' [IEM] alongside the presentation of autism. This is important in the context that science is starting to more fully understand how a diagnosis of autism rarely exists in some sort of diagnostic vacuum (see here) and quite a lot of different types of comorbidity seem to be 'over-represented'. I'd be inclined to suggest that this detail provides even stronger evidence for how IEM and at least some autism represent an important partnership.

Finally, I refer back to one of the statements made by the authors on "recommendations for further investigations." They suggest that those presenting with: "A positive family history of metabolic disease... Symptoms or signs are triggered by food intake (esp high protein content foods), fever, fasting, surgery (catabolism)... Feeding difficulties, food refusal, failure to thrive, eating disorders combined with symptoms of myopathy or fatigue... Mental retardation and/or regression... Epilepsy, episodes of lethargy or confusion... Dysmorphic feature" should be considered for further investigations. Yes, some of the language is not what I would use and yes, that covers quite a bit of clinical ground but screening is the first part to ruling out such a potential organic correlate of some autism and may in some cases, yield potentially important insights (see here)...

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[1] Simons A. et al. Can psychiatric childhood disorders be due to inborn errors of metabolism? European Child & Adolescent Psychiatry. 2016. Sept 30.

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Simons A, Eyskens F, Glazemakers I, & van West D (2016). Can psychiatric childhood disorders be due to inborn errors of metabolism? European child & adolescent psychiatry PMID: 27695954

Mitochondrial response to BCKDK-deficiency and 'some' autism

I'll admit to being pretty fascinated by the Branched Chain α-Keto acid Dehydrogenase Kinase (BCKDK) gene. As per previous blog entries about this gene (see here and see here) and the important biological step it plays in the metabolism of the branched-chain amino acids (BCAAs), at least one 'form' of autism might be particularly sensitive to issues with it [1]. I take it you've heard of the idea that the autisms (plural) might be a better description of autism? If you haven't, here is a peer-reviewed take on it [2]...

I'm happy to report that science continues to study this gene; its biology and it's associations with "a novel dietary-treatable form of autism" as per the findings reported by Oyarzabal and colleagues [3]. The focus of the Oyarzabal paper was to study the "mitochondrial response to the BCKDK-deficiency" potentially brought about for example, when there are issues with the BCKDK gene given its links to the mitochondria matrix. This work also takes on particular relevance given the idea that mitochondrial issues - mitochondria: the powerhouse of cells - might not be something entirely new to at least some autism (see here for example).

Anyhow, fibroblasts were the starting material and the measurement of "bioenergetics, ultra-structural and dynamics parameters" of fibroblasts from those who had BCKDK-deficiency. Although not totally au-fait with all the science included in the paper, the authors report results on: "a general bioenergetics depletion that could affect the mitochondrial dynamics and cell fate." They even reported complementary findings following a: "Knockdown of BCKDK gene in control fibroblasts" and mention of some findings relevant to maple syrup urine disease (MSUD) in light of the involvement of the BCAAs there. In short: "All these data gives us a clue to understand the positive dietary response to an overload of branched-chain amino acids."

This is an exciting area of autism research pertinent to the idea that (a) there may be various types of autism characterised by various different genetic and biological factors being involved, and (b) the possibility that at least some autism might stem from one or more inborn errors of metabolism is gaining ground (see here) and hence might be potentially 'treatable'. For that last point I'm minded to take you back to a recent post on phenylketonuria and autism (see here) and some more recent [peer-reviewed] research talking about 'Succinic Semialdehyde Dehydrogenase Deficiency Presenting as Autism Spectrum Disorder' [4]. Dare I even present the idea of carnitine issues falling into this area?

Screening for such inborn errors of metabolism seems to be the important conclusion; screening not assuming nor guessing nor making grand generalisations. Just screening.

Music: the glorious music accompanying the film Interstellar has to be the one for today in light of new discoveries in recent days...

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[1] Novarino G. et al. Mutations in BCKD-kinase lead to a potentially treatable form of autism with epilepsy. Science. 2012 Oct 19;338(6105):394-7.

[2] Poot M. Towards identification of individual etiologies by resolving genomic and biological conundrums in patients with autism spectrum disorders. Mol Syndromol. 2013 Jun;4(5):213-26.

[3] Oyarzabal A. et al. Mitochondrial response to the BCKDK-deficiency: Some clues to understand the positive dietary response in this form of autism. Biochim Biophys Acta. 2016 Jan 22. pii: S0925-4439(16)30003-5.

[4] Gogou M. et al. Succinic Semialdehyde Dehydrogenase Deficiency Presenting as Autism Spectrum Disorder. Indian J Pediatr. 2016 Jan 25.

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Oyarzabal A, Bravo-Alonso I, Sánchez-Aragó M, Rejas MT, Merinero B, García-Cazorla A, Artuch R, Ugarte M, & Rodríguez-Pombo P (2016). Mitochondrial response to the BCKDK-deficiency: Some clues to understand the positive dietary response in this form of autism. Biochimica et biophysica acta PMID: 26809120

Autism in phenylketonuria (PKU)

"Autism has been reported in untreated patients with phenylketonuria."

Indeed it has, as the paper by Sameh Khemir and colleagues [1] revisits something of a long known about association whereby the archetypal inborn error of metabolism that is phenylketonuria (PKU) has been linked to the presentation of autism or autistic traits [2].

Looking at 18 participants diagnosed with PKU, Khemir et al "report their clinical, biochemical and molecular peculiarities" (authors words not mine) and how 15 of the 18 presented with autism as per assessment with "The Childhood Autism Rating Scale and the Autism Diagnostic Interview-Revised." Following some molecular biological analysis specifically with the "phenylalanine hydroxylase gene" in mind (a key player in PKU), the authors reported on various potentially important issues but "no correlation between autism and mutations affecting the phenylalanine hydroxylase gene."

I have a lot of time for PKU on this blog. Not only because PKU represents one of the best examples of how certain foods for some can affect development and onwards mental health (see here) but also because some of the other intervention options for PKU (outside of low phenyalanine diet) might hold some promise for some autism too (see here). Indeed, the idea that tetrahydrobiopterin (BH4) - an important cofactor for phenyalanine hydroxylase and related aromatic amino acid hydroxylase enzymes - might be quite good at helping to mop up excess phenylalanine and other compounds continues to find favour in some autism research circles. Dare I also mention the effects of BH4 on tryptophan and 5-HTP as potentially being relevant to some autism too? (see here)

In many parts of the world, the advent of the newborn screening program (built on the genius of people like Robert Guthrie and others) has all but eradicated untreated PKU and perhaps impacted on the number of people presenting with autism too. There remain however, challenges in certain areas of the globe, where people are not so fortunate to have such screening measures in place. Indeed, Khemir and colleagues report their results based in Tunisia and Algeria; other geographically related areas might also benefit from the implementation of such screening practices [3].    

Just before I go, there is one last comment to make on something discussed by Khemir and colleagues: "age of diet onset was the determining factor in autistic symptoms' evolution." Diet, as I've mentioned, refers to the low phenylalanine (low protein) diet commonly used to manage PKU. It appears that there might be more to see in terms of how long PKU goes untreated and the progression of autistic traits similar to other descriptions, particularly the findings reported by Baieli and colleagues [4]: "None out of 62 patients with classic PKU diagnosed early met criteria for autism. In the group of 35 patients diagnosed late, two boys (5.71%) ages 16 and 13 years fulfilled the diagnostic criteria for autism."

Diet potentially affecting the presentation of autism eh? I'll be coming to the paper by Oyarzabal and colleagues [5] soon enough built on some related research...

Music: Led Zeppelin - Rock And Roll.

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[1] Khemir S. et al. Autism in Phenylketonuria Patients: From Clinical Presentation to Molecular Defects. J Child Neurol. 2016 Jan 12. pii: 0883073815623636.

[2] Miladi N. et al. Phenylketonuria: an underlying etiology of autistic syndrome. A case report. J Child Neurol. 1992 Jan;7(1):22-3.

[3] Saad K. et al. ADHD, autism and neuroradiological complications among phenylketonuric children in Upper Egypt. Acta Neurol Belg. 2015 Dec;115(4):657-63.

[4] Baieli S. et al. Autism and phenylketonuria. J Autism Dev Disord. 2003 Apr;33(2):201-4.

[5] Oyarzabal A. et al. Mitochondrial response to the BCKDK-deficiency: Some clues to understand the positive dietary response in this form of autism. Biochim Biophys Acta. 2016 Jan 22. pii: S0925-4439(16)30003-5.

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Khemir S, Halayem S, Azzouz H, Siala H, Ferchichi M, Guedria A, Bedoui A, Abdelhak S, Messaoud T, Tebib N, Belhaj A, & Kaabachi N (2016). Autism in Phenylketonuria Patients: From Clinical Presentation to Molecular Defects. Journal of child neurology PMID: 26759449

Autism manifests across a range of genetic and metabolic syndromes

"Autism spectrum disorder (ASD) phenomenology is reported to be more common in individuals with some genetic syndromes than in the general population."

That was the starting point for the systematic review and meta-analysis published by Caroline Richards and colleagues [1] who set about 'synthesising' the various peer-reviewed data "to provide accurate estimates about ASD phenomenology in genetic and metabolic syndromes." A scan of the cumulative literature in this area ("168 papers reporting the prevalence of ASD phenomenology") revealed that autism presentation is indeed a feature of quite a few conditions compared with "the general population taking the current estimate of one in 68 people."

To those with an eye on the autism research scene the list of conditions where autism manifests is not likely to be a surprise. Rett syndrome represented one of the conditions where relative risk and odds ratio "compared to the general population" was highest. Tuberous sclerosis (TS) is also mentioned as is neurofibromatosis type 1 (NF1). I was however a little surprised that Fragile X syndrome was a little further down the frequency line than it was - "male individuals only 30%; mixed sex 22%" - given the quite classical association that I remember being discussed with autism. Down syndrome is also mentioned and perhaps reflects an increasing interest in autism being comorbid that has graced this blog previously (see here) as has the growing connection with Del22 (see here).

The authors conclude by calling for more research "including how ASD in genetic and metabolic syndromes differs from idiopathic autism [autism spontaneously arising with unknown aetiology] and what that can tell us about the mechanisms underlying ASD." This is a discussion also included in a recent paper by Sacrey and colleagues [2]. I would agree with those sentiments within the context of the Richards paper providing more evidence for the plurality of autism - the autisms (see here). I might add that if one extends the findings to autism comorbid to metabolic disorders (as in conditions such as the various inborn errors of metabolism) (see here), further details may indeed be revealing about just how many types of autism there may be, and where desired, what intervention options may present (see here).

Music: The Lumineers - Ho Hey.

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[1] Richards C. et al. Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis. Lancet Psychiatry. 2015. Sept 1.

[2] Sacrey LR. et al. Early Infant Development and Intervention for Autism Spectrum Disorder. J Child Neurol. 2015 Aug 31. pii: 0883073815601500.

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Caroline Richards, Christopher Jones, Laura Groves, Jo Moss, & Chris Oliver (2015). Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis The Lancet Psychiatry

The autisms, case reports and two 'intervention' options

I'm looking at two papers today which I'd like to think cover the title of this post pretty well dealing with the plurality of autism - the autisms - and the idea that intervention or management-wise, there is no 'one size fits all' when it comes to the autisms.

First up are the findings reported by Ziats and colleagues [1] who presented results for a child - "A 4-year-old male with autism and two episodes of neurodevelopmental regression" - who was also found to have a "mutation in the TMLHE gene, which encodes the first enzyme in the carnitine biosynthesis pathway, and concurrent carnitine deficiency." Supplementation with carnitine (see here) seemed to lead to some interesting changes in the developmental profile for this boy such that: "the patient's regression ended, and the boy started gaining developmental milestones."

Accepting that this was another example of the N=1 and autism (see here) I was rather interested in these results having previously blogged about issues with the TMLHE (trimethyllysine hydroxylase) gene in relation to autism (see here). The source of that previous post was the paper from Patricia Celestino-Soper and colleagues [2] (open-access) who concluded that: "TMLHE deficiency is a risk factor for autism" and quite a bit more should be done to screen for such issues. I wouldn't disagree with those sentiments (see here).

Next up are the results reported by Serret and colleagues [3] (open-access) who presented findings based on two participants "diagnosed with autism spectrum disorders in childhood and presented regression with catatonia features and behavioural disorders after a stressful event during adolescence." Further: "both patients presented mutation/microdeletion of the SHANK3 gene, inducing a premature stop codon in exon 21." Issues with SHANK3 have been reported in relation to autism previously.

Authors reported that: "lithium therapy reversed clinical regression, stabilized behavioural symptoms and allowed patients to recover their pre-catatonia level of functioning, without significant side effects." Further: "These cases support the hypothesis of a specific SHANK3 phenotype" and that lithium might hold some favour in improving clinical presentation in those cases.

Again, I was interested in the Serret findings with the caveat about their also using the case study approach in their paper. Lithium is an interesting compound that has graced this blog a few times in relation to its potential 'anti-suicide' correlating properties (see here) and as a possible management tool when it comes to the presentation of mood disorders comorbid to a diagnosis of autism (see here). Accepting that lithium has its own potential side-effects profile, the idea that cost-benefits might be calculated and if so deemed more benefit and less cost subsequently applied to 'some' autism, is an interesting prospect.

Reiterating my opening paragraph, what the Ziats and Serret papers serve to tell us is that within 'the autisms' there may be many different roads to a diagnosis of autism and that under the diagnostic label of 'autism', genetics, biochemistry and subsequent intervention/management strategies may vary from person to person. As I've said before, receipt of a diagnosis of autism (when it is eventually received) should be a starting point for further inquiry not the 'finishing line'.

That comorbidity - if I can still call it that - might also be a 'target' for analysis and investigation is also an important point raised and further asks more questions about the value of intervening on said comorbidity and the possible knock-on effects on the presentation of more core autism symptoms (see here). Y'know something like what is emerging in the body of research looking at anxiety and autism (see here).

With the body of work linking this, that and t'other to autism I'm starting to think that some further resources might be needed to pull all the available peer-reviewed information together in terms of what factors have been linked to those 'autisms'. I've always been very partial to autism research looking at inborn errors of metabolism (IEMs) as a starting point for investigations (see here) given both the data on overlap and even the idea that some of the various interventions for specific IEMs might hold promise for 'some' autism (see here). Analysis of things like rare genetic variations also being linked to the appearance of autism (see here) ties into the IEM investigations and perhaps represents the next tier of evaluation, bearing in mind the reduced costs of things like whole genome sequencing these days set within the perspective of personalised medicine (see here). Environment, bearing in mind the range of factors this might cover, should also be included in any diagnostic work-up based on the evolving science connecting something like infection to autism onset for some (see here and see here). There are various tests that could be performed covering a whole slew of potential infective agents (see here).

This is just a rough-and-ready idea of where autism research and practice could go with this but much like the pathways to diagnosing and managing bowel issues when comorbid to autism for example (see here), a general diagnostic roadmap is perhaps indicated...

Music: Years & Years - King.

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[1] Ziats MN. et al. Improvement of regressive autism symptoms in a child with TMLHE deficiency following carnitine supplementation. Am J Med Genet A. 2015 May 5.

[2] Celestino-Soper PB. et al. A common X-linked inborn error of carnitine biosynthesis may be a risk factor for nondysmorphic autism. Proc Natl Acad Sci U S A. 2012 May 22;109(21):7974-81.

[3] Serret S. et al. Lithium as a rescue therapy for regression and catatonia features in two SHANK3 patients with autism spectrum disorder: case reports. BMC Psychiatry 2015, 15:107.

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Ziats MN, Comeaux MS, Yang Y, Scaglia F, Elsea SH, Sun Q, Beaudet AL, & Schaaf CP (2015). Improvement of regressive autism symptoms in a child with TMLHE deficiency following carnitine supplementation. American journal of medical genetics. Part A PMID: 25943046




Serret, S., Thümmler, S., Dor, E., Vesperini, S., Santos, A., & Askenazy, F. (2015). Lithium as a rescue therapy for regression and catatonia features in two SHANK3 patients with autism spectrum disorder: case reports BMC Psychiatry, 15 (1) DOI: 10.1186/s12888-015-0490-1