Folate and autism: more questions than answers

Athenian sunset @ Paul Whiteley

I don't know if you could tell but my previous few blog posts were a sort of stand-in whilst I took a few days off. Not exactly repeats of favourite soap operas or anything like that, but more like watching some pre-recorded non-league football (soccer) compared to the Premiership live. Suffice to say that I'm back now and ready to press on with some 'proper' posts.

Whilst away I've been thinking quite a bit about the paper from Rebecca Schmidt and colleagues* on maternal folic acid intake and offspring risk of autism spectrum conditions discussed in this post. Don't get me wrong I'm not disputing their findings of anything like that; recognising that is, the retrospective 'tell me what you did' methodology used and how studies of association are just that: studies of association.

The media attention following the Schmidt paper however painted an interesting picture of folic acid supplementation and autism. As perhaps expected, some outlets have taken up the 'preventative' side of folic acid supplements with headline such as this one: 'Consuming folic acid during early pregnancy cuts risk of an autistic child'. Maybe it's just me, but I don't believe that headlines like this paint as accurate a picture of the folic acid-autism link as perhaps the research literature suggests, as in this post I try and explain why.

There is no denying the important functions that folic acid supports not just to the developing foetus during early pregnancy but also in adult health, as for example seen in the growing literature on folic acid reducing the risk of stroke.

With autism in mind, the literature on folic acid is however a little more muddled in terms of the early days/months/years effects of supplementation and indeed the cycle of compounds in which folic acid finds itself in:

• Eugene Rogers** published a speculative paper (in a speculative journal!) a few years back, asking whether supplementation with folic acid during pregnancy has influenced natural selection and further autism prevalence. The theory goes that children who carry previously discussed SNPs in genes like everyone's favourite Scrabble classic gene, MTHFR, which might influence the effectiveness of folate, are surviving in greater numbers as a result of mum's increased folate intake. After birth, kids with mutations in the MTHFR gene still need lots more folate but aren't getting enough; hence important processes like methylation aren't able to be carried out optimally and behavioural consequences are apparent (see here). Before you roll your eyes and click away, there is some evidence (albeit limited) to back up this hypothesis. So, SNPs in MTHFR in autism: check; elevations in homocysteine in kids with autism: check; suggestions of hypomethylation in cases of autism (and mums with children with autism): check. Some evidence at least, although as always I could be cherry-picking the data.
• Beard and colleagues*** in a similar stance, also asked the question (in the same journal) as to whether excess folic acid supplementation might be a risk factor for autism. I'm slightly less convinced by their associations and presented data, but the question of whether "too much folic acid may result in nervous tissue damage associated with autism" is an interesting one particularly in light of research like this from Junaid and colleagues**** and over 1000 genes suspected to be 'dysregulated' by high folic acid supplementation.
• The older literature on folic acid and autism also carries some interesting papers. So, this paper by Gillberg and colleagues***** reports results from a very small study on the supplementation of folic acid to boys diagnosed with autism and "the fragile X syndrome". Reviewing the evidence for a larger effect from folic acid supplementation for Fragile X syndrome, it has to be said however that it is not all that impressive (here).
• I've talked before about an important piece of research which looked at folate receptor autoantibodies in cases of autism. In this scenario, folic acid is not necessarily the main issues but rather the fact that the folate receptors may not be functioning optimally, and so for example, are influencing the delivery of 5-MTHFR to cells. The suggestion from this (and another******) paper was that supplementation with folinic acid may be a better option. I shall at this point reiterate that medical advice is neither given nor intended in this or any post on this blog.

I hope I've made a preliminary case for some greater inspection of folic acid and its relations in cases of autism in light of how the recent Schmidt findings have been disseminated in some quarters. Recognising that vitamins and minerals are readily available to everyone combined with the possibility of a suggestion that increased folic acid intake during pregnancy might 'offset' the risk of offspring autism, to my mind makes for a strong requirement for some balanced advice on this matter.

The picture accompanying this post is a holiday snap from some family vacation time in Greece. Warm, very warm summer days and nights, cicada making their music and cycling seemingly becoming very popular in Greece (with the usual safety caveats suspended in quite a few cases). So to finish some Greek pop music from Mr Michalis Hatzigiannis. Ελλάδα γεια σου.

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* Schmidt RJ. et al. Maternal periconceptional folic acid intake and risk of autism spectrum disorders and developmental delay in the CHARGE (CHildhood Autism Risks from Genetics and Environment) case-control study. American Journal of Clinical Nutrition. May 2012.
DOI: 10.3945/​ajcn.110.004416

** Rogers EJ. Has enhanced folate status during pregnancy altered natural selection and possibly Autism prevalence? A closer look at a possible link. Medical Hypotheses. 2008; 71: 406-410.

*** Beard CM. et al. Is excess folic acid supplementation a risk factor for autism? Medical Hypotheses. 2011; 77: 15-17.

**** Junaid MA. et al. Folic acid supplementation dysregulates gene expression in lymphoblastoid cells--implications in nutrition. Biochemical & Biophysical Research Communuications. 2011; 412: 688-692.

***** Gillberg C. et al. Folic acid as an adjunct in the treatment of children with the autism fragile-X syndrome (AFRAX). Developmental Medicine & Child Neurology. 1986; 28: 624-627.

****** James SJ. et al. Efficacy of methylcobalamin and folinic acid treatment on glutathione redox status in children with autism. American Journal of Clinical Nutrition. 2009; 89: 425-430.

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Schmidt RJ, Tancredi DJ, Ozonoff S, Hansen RL, Hartiala J, Allayee H, Schmidt LC, Tassone F, & Hertz-Picciotto I (2012). Maternal periconceptional folic acid intake and risk of autism spectrum disorders and developmental delay in the CHARGE (CHildhood Autism Risks from Genetics and Environment) case-control study. The American Journal of Clinical Nutrition, 96 (1), 80-9 PMID: 22648721

Autism: getting some interference from interferon?

Autism research has on more than one occasion looked at the possibility that there is an immune component to at least some cases of autism. Indeed I hope I am not being too scientifically reckless when I say that immune involvement seems to be becoming quite a central finding to a proportion of people on the autism spectrum as per the results from researchers like Harumi Jyonouchi and Paul Ashwood. The big questions remain however: what are the central immune issues, who exactly on the spectrum are immune findings most pertinent to, and what comes first: autism or immune involvement? (I don't have the answers to these questions by the way, although have recently looked to Paul Patterson for some interesting directions).


Putting such 'chicken or egg' philosophical issues to one side, I offer another review-type entry with the immune system in mind with this post on autism and the interferons. A description first. If you've ever heard mention of the interferons, most likely it will have been referencing the cytokine interferon-gamma or IFN-gamma or IFN-γ (if you prefer the Greek character). Quite a good and comprehensive overview of IFN-γ is this one by Schroder and colleagues* (full-text). 


Bear however in mind that IFN-γ is but one member of family of proteins associated with lots of processes related to the immune system including macrophages (the 'big eaters' of the immune system) following the detected presence of a pathogen (bacteria, parasite, virus). The interferons also play quite an important anti-viral role as per their name.


Allowing for the fact that our immune systems' are probably always to some degree 'activated' given our continually interacting with our environment and all the bugs 'n stuff in it, one can perhaps see that the presence of significant elevations in levels of the interferons might be an important marker as to current the state of the immune system. Importantly, whether it is fighting infection or at least thinks its fighting an infection and how long the fight goes on for. 


So what's the story of interferon and autism? Quite a bit actually:

• Vijendra Singh** was one of the first to report on the presence of elevations in plasma levels of IFN-γ (and another cytokine, IL-12, a stimulator of IFN-γ) among participants with autism compared to asymptomatic controls. Similar increases in levels of IFN-γ in cases of autism were also noted by Croonenberghs and colleagues*** who reported on a few other relevant details also such as "a trend toward a significantly increased production of IL-6" despite no significant group differences between autism and controls. IL-6 you say? Similar findings of elevated levels of IFN-γ in autism have been replicated a few more times bearing in mind the different tissues analysed (here, here and here). 
• Gene Stubbs**** reported results for a small (very small!) participant group with autism based on levels of IFN-alpha (IFN-α) suggesting elevations compared to an even smaller control group. I was intrigued by this preliminary finding given that alpha interferon, normally used as pharmacotherapy for certain types of cancer (here), as well as being involved in immune function also (a) has the propensity to induce neuropsychiatric symptoms (here) and (b) exhibits some opioid activity as per its analgesic effect and affinity for certain types of opioid receptor (here). All that being said, I can't seem to find any other paper in the research literature which has looked at IFN-α in cases of autism. Perhaps it just isn't interesting enough (don't even ask about the other interferons).

There are a few other small details to add to the work in progress that is the interferons and autism.


As you will probably have noted, examination of the interferons has, in the majority of studies, been done alongside other biological parameters of the immune system, specifically other cytokines such as the various interleukins (those compounds prefaced by IL). What this perhaps implies is that the various findings on the interferons is part and parcel of a wider set of immune-related functions and parameters. The trick is determining which ones might be core to autism, and which ones are just after-effects.


Inflammation also features quite a bit in this story as it seems to have done based on other autism research. As with many cytokines and the blurring which comes with regards to (a) inflammation being universally a bad thing - it's not, (b) the black or white issue of being pro- or anti-inflammatory - it's not so simple, the relationship between interferons and inflammation is just as complicated. So for example, there is evidence that as well as being pro-inflammatory, interferons might also limit the inflammatory response as per this article by Sauer and colleagues***** (full-text). Just think Anakin Skywalker and his 'mixed' relationship with the Force as a kind of template.


Finally, I stumbled across this interesting paper by Barker and colleagues****** just to throw into the mix, and their suggestion that IFN-γ may be able to influence vitamin D levels. I'm interested in this paper on so many levels: the IFN-γ levels noted in cases of autism, vitamin D potentially being related to autism (and a few other things), etc. Accepting that Barker looked at a specific condition associated with 'inflammatory stress' and the old adage about correlation not being the same as causation, one has to wonder whether this may also impact on the interferon findings noted in autism. Indeed whether chronic activation of interferons and other immue parameters towards inflammation, may have much more far-reaching consequences than just immune involvement in autism. Gut permeability perhaps?


To close, preaching is what Papas do best so why should we stop? (and we do it oh so well).


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* Schroder K. et al. Interferon-γ: an overview of signals, mechanisms and functions. Journal of Leukocyte Biology. 2004; 75: 163-189.


** Singh VK. Plasma increase of interleukin-12 and interferon-gamma. Pathological significance in autism. Journal of Neuroimmunology. 1996; 66: 143-145.


*** Croonenberghs J. et al. Activation of the inflammatory response system in autism. Neuropsychobiology. 2002; 45: 1-6.


**** Stubbs G. Interferonemia and autism. JADD. 1995; 25: 71-73.


***** Sauer I. et al. Interferons limit inflammatory responses by induction of tristetraprolin. Blood. 2006; 107: 4790-4797.

****** Barker T. et al. Circulating interferon-γ correlates with 1,25(OH)D and the 1,25(OH)D-to-25(OH)D ratio. Cytokine. June 2012.

The mixed up world of brain-derived neurotrophic factor and autism

I have to say that I am becoming quite settled with my new found interest in blogging after some 16 months of running this blog. Indeed as hopeful as I am that my posts are accurate, balanced and of some interest to at least someone, the whole process of writing a blog entry is also quite good for me and my learning curve on the multitude of research that has been, and continues to be done on autism and things related. Makes you wonder whether blogging would ever count as CPD?

A case in point is this entry on the various research examining a role / connection between brain-derived neurotrophic factor (BDNF) and autism. I've heard mention of BDNF down the years but never considered myself to be fully capable of saying what the stuff is and what has been found in relation to autism. I'm trying to remedy that situation with this post, so let's see how I do.

BDNF is probably best described as a protein, a member of the neurotrophin family, and a growth factor for neurons and synapses. Quite a good overview of the neurotrophins can be found here* by Allen & Dawbarn (full-text). The link between BDNF and neuronal health is perhaps why the molecule has found quite a bit of interest in autism research circles and in particular, its proposed link to the serotonergic system - serotonin having quite a long history in relation to autism.

It is worth point out that BDNF levels and function are known to be influenced by several factors. So, age and gender seem to be able to affect levels of BDNF (here) as does specific pathology such as depression and schizophrenia (here) depending on where you look and what medium you look in. The neuronal 'plasticity' relationship to BDNF (among quite a few other actions I might add) seems to have been taken up by quite a few authors; particularly adult plasticity, contributory perhaps to the more lifelong view of brain plasticity which predominates these days over older theories of 'after childhood, set in stone'.

With autism in mind, there is a body of evidence on BDNF which suggests a few things albeit not exactly consistently:

• I am a little bit unsure whether BDNF is meant to be 'generally' high or low in cases of autism. Accepting the factors which can influence BDNF listed above, there seems to be some conflicting evidence on findings related to blood/plasma. So for example, this paper by Al-Ayadhi** (full-text), an author mentioned in previous posts, reported lower levels of serum BDNF in their cohort of children with autism. This contrasts with this paper by Connolly and colleagues*** who reported elevations in BDNF. Just to complicate matters further Lisa Croen and colleagues**** (full-text) reported no significant differences in blood concentrations of BDNF in either mums mid-pregnancy nor their young offspring subsequently diagnosed with autism compared with asymptomatic and learning disability control participants. I might be comparing apples and oranges at different times of year, but suffice to say that results are not yet clean-cut.
• When it comes to genes and BDNF in cases of autism, the waters aren't really any less muddy. This paper by Correia and colleagues***** reported elevations in plasma BDNF in their autism cohort but the source of the increase did not seem to stem from issues with the BDNF gene. Without being an expert on all things genetic, I think this finding might also tie into the results published by Garcia and colleagues****** who suggested that BDNF elevations might not be "transcriptionally driven" (see here for a summary of mRNA). There are other studies looking at other features of BDNF seemingly reporting contrasting findings such as decreased BDNF and anti-apoptotic function (here) and SNPs in the BDNF gene in autism (here and here). The message continues: it's complicated.

One could perhaps suggest that the various results relating to BDNF in autism mirror quite a few other areas of research insofar as not being able to make consistently reproducible statements of fact about autism. Having said that there are perhaps lessons to be learned from compounds such as BDNF in terms of fluctuating levels throughout the lifetime, differences depending on the tissue or biological medium being analysed and some degree of individual responsiveness behind the various findings so far. The fact that BNDF levels might also show involvement in other conditions, such as depression for example, is also worth bearing in mind.

Finally, and without trying to tie every single finding in autism back to gut bacteria or other of my areas of interest, there may yet be something in this relationship accounting for at least some of the BDNF findings in autism. I note for example this paper by Bercik and colleagues******* (similar work commented on here) which suggested that in mice at least, disruption of the gut microflora by antibiotic use seemed to increase brain levels of BDNF.

An example of a real gut-brain interface in action?

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* Allen SJ, Dawbarn D. Clinical relevance of the neurotrophins and their receptors. Clinical Science. 2006; 110: 175.191.

** Al-Ayadhi LY. Relationship between Sonic hedgehog protein, brain-derived neurotrophic factor and oxidative stress in autism spectrum disorders. Neurochemical Research. 2012; 37: 394-400.

*** Connolly AM. et al. Brain-derived neurotrophic factor and autoantibodies to neural antigens in sera of children with autistic spectrum disorders, Landau-Kleffner syndrome, and epilepsy. Biological Psychiatry. 2006; 59: 354-363.

**** Croen LA. et al. Brain-derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) Study. Autism Research. 2008; 1: 130-137.

***** Correia CT. et al. Increased BDNF levels and NTRK2 gene association suggest a disruption of BDNF/TrkB signaling in autism. Genes, Brain & Behavior. 2010; 9: 841-848.

****** Garcia KL. et al. Altered balance of proteolytic isoforms of pro-brain-derived neurotrophic factor in autism. Journal of Neuropathology & Experimental Neurology. 2012; 71: 289-297.

******* Bercik P. et al. The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology. 2011; 141: 599-609.

Fetal alcohol syndrome

Pregnancy is a special time for both prospective mum and dad. OK, dad's role is a little more 'peripheral' at this stage; more about support and understanding, doing that little more around the house - 'its called a washing machine' - and generally just being there when, for example, the words 'could you nip out and get me some pickled onions darling' are said late at night.

Pregnancy is also an important time for both foetal (English-spelling) and maternal health; as information comes thick and fast about health, diet, nutrition and exercise. So, lots of things to do (exercise, folic acid(!), etc) and lots of things to avoid (smoking, drinking alcohol, eating raw shellfish, old paintwork, etc). Whilst there is some good evidence behind these dos and don'ts, in recent times some of the suggestions have been the source of some debate. 


Take for example the advice about drinking alcohol during pregnancy. Down the years, there's been an almost operatic battle about what is and isn't a safe level of alcohol consumption during pregnancy. It seems some days expectant mums are advised no alcohol at all during pregnancy, other days reports come out saying a little moderate consumption is probably going to be alright. I can perhaps see how it all could be quite confusing (as per other health advice - see here). 


More confusion has arrived at the time of writing, as several studies have recently emerged looking at alcohol consumption during pregnancy and future offspring development (see here) followed by quite a few headlines such as this one from the BBC "Moderate drinking in early pregnancy branded 'safe'". I might add that I am not endorsing this or any other stance but would also direct readers to this post by the NHS Choices website for some balance regarding the publications in question.


I have to say that I always get a little bit nervous when something is 'branded safe'; thinking back to a certain British Politician and a daughter's hamburger a few years back. Indeed, these latest studies got me thinking about alcohol and pregnancy and how, if it is so safe, do we arrive at something called fetal alcohol syndrome (FAS). I want to talk about FAS with autism in mind but tread very, very carefully here so as not to make connections where none exist.


A short description first. FAS is quite a nebulous term characterised by quite a lot of different symptoms covering everything from cognitive and learning issues to specific facial features to other overlapping features more readily covered under the more general term fetal alcohol spectrum disorder (FASD). Some quite recent research (here) has reiterated the cognitive side of things as being central to the effects of alcohol exposure.


With autism - autistic behaviours - in mind, the research path goes something like this:

• Various cases of the presence of FAS and autism are dotted around the research landscape. So, this paper by Nanson* seems to be one the earliest, describing six cases of children with FAS who also "fulfill the criteria for diagnosis of autism". Followed in succession by this paper by Harris and colleagues** and a few others.
• I was drawn to this short reply by Eric Fombonne*** (click 'show summary') on the question of an association between FAS and autism in light of the previous findings. Drawn to it because some good issues are raised here, not least that autism is not universal to all children with FAS (2% of cases is the suggestion) and also that the other features normally accompanying FAS are not normally associated with autism. Indeed, there is a strong argument in this piece that the coincidence of autism in FAS is nothing more than just a chance finding as per the recent autism prevalence figures.
• Further analysis of the presentation of behavioural features in cases of autism vs. FASD has also revealed some interesting issues. Bishop and colleagues**** described a comparative study based on ADOS and ADI measures in both groups. They suggested that whilst social issues like appropriate behaviour and peer relationships were common between the groups, the core 'social affect' behaviours (as it will become) seem to be firmly rooted in autism not FASD. The lack of other control groups (speech and language delay, learning disability, etc) is a bit of a short-coming to this study but the results still hold up demonstrating differences between autism and FASD.

There are other papers mentioning autism and FAS / FASD but I have to say the suggestion of a link between these conditions is rather unimpressive based on the current data. That's not to say that certain behaviours linked to autism might not also be present in FAS / FASD, but that autism as a diagnostic package is likely not to show strong associations with these conditions.

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* Nanson JL. Autism in fetal alcohol syndrome: a report of six cases. Alcoholism, Clinical & Experimental Research. 1992; 16: 558-565.

** Harris SR. et al. Autistic behaviors in offspring of mothers abusing alcohol and other drugs: a series of case reports.. Alcoholism, Clinical & Experimental Research. 1995; 19: 660-665.

*** Fombonne E. Ask the Editor: Is exposure to alcohol during pregnancy a risk factor for autism? JADD. 2002; 32: 243.


**** Bishop S. et al. Re-examining the core features of autism: a comparison of autism spectrum disorder and fetal alcohol spectrum disorder. Journal of Child Psychology & Psychiatry & Allied Disciplines. 2007; 48: 1111-1121.

GABA Dabba Doo

I'm probably setting myself up for a fall with this quite descriptive post on GABA - gamma aminobutyric acid in relation to autism spectrum conditions given my amateur status in the knowledge stakes regarding the various neurotransmitters. I am however going to chance my luck because more and more frequently GABA seems to be cropping up in the peer-reviewed literature on autism.

Indeed I don't know whether it is just me, but other neurotransmitters such as serotonin (5-HT) seem to be experiencing a slight drop in popularity in autism research circles these days, whilst transmitters like GABA and glutamate, are in the ascendancy. As per every post on this blog (a) no medical advice is intended or given, and (b) always treat my observations with a healthy dose of scepticism.

What is GABA?

Well, I've mentioned glutamate already and indeed glutamate is the core material for making GABA alongside the active form of vitamin B6, pyridoxal phosphate (PLP or P5P) used as a cofactor. The enzyme glutamate decarboxylase (GAD) is essential for this transformation from excitatory neurotransmitter (glutamate) to inhibtory neurotransmitter (GABA). Brain synthesis is an important part of GABA given that it finds some difficulty crossing the blood-brain barrier. Keep in mind both PLP and GAD for later on in this post.

What does it do?

Well, it's a neurotransmitter with corresponding GABA receptors dotted around the central nervous system including in the region of the 'second brain' that is the gastrointestinal tract (here) similar to other neurotransmitters (here). GABA is also described as an inhibitory neurotransmitter (here) similar to glycine; a sort of yin and yang to the excitatory neurotransmitters which modulate the firing of neurons; GABA (generally) decreasing their likelihood of firing.

Over-zealous neuronal firing caused by an 'imbalance' between excitatory and inhibitory neurotransmitters is thought to be involved in conditions like epilepsy (here) and the reason why certain compounds that increase GABA levels in the brain also possess anticonvulsant properties (here). There is also some speculation linking the use of a ketogenic diet and increases in brain GABA synthesis to account for the anticonvulsant observations noted (here) for example. Should I mention that GABA might also possess some anti-inflammatory action (here) too?

So a quick recap: glutamate, GAD and PLP in the brain (and other places) make GABA, an inhibitory neurotransmitter which dampens down neuronal firing and potentially the reason why some antiepileptics (and other compounds) which enhance GABA production/action work the way they do.

Let the cherry-picking begin: GABA and autism.

Where to start...mmm. GABA has been looked at from several perspectives in cases of autism falling into some general categories to include: (a) issues with the receptors for GABA in the brain, and (b) issues with GAD involved with the synthesis of GABA from glutamate. There are other areas (such as autoantibodies to GABAergic neurons)  but the lion's share of research seems to fall into one of these two categories.

(a) GABA receptors are basically the bedfellows of GABA. Several types of GABA receptor are currently known about and have been examined with autism in mind.

• Quite a bit of research has been done in this area so I am indeed cherry-picking. The comorbidity of autism and epilepsy is obviously a point of real interest given the function of GABA and its receptors as described in this paper by Kang & Barnes*.
• Various authors have reported on issues with GABA receptors in cases of autism; in the majority suggesting reduced receptor numbers in various parts of the brain (see here, here and here).
• The genetics of GABA receptors have also been the topic of some research although not wholly convincing in providing an effect (see here and here). I don't want to seem unduly biased against any genetic link to GABA receptors and autism so will balance that last sentence by noting the evidence on for example, gene-gene interactions and GABA receptor genes in autism (see this paper by Ma and colleagues** full-text).

(b) GAD has been mentioned in passing previously on this blog in relation to the imbalance seemingly present between glutamate/glutamine in cases of autism. I can see why this is such an attractive area of study with autism in mind, covering not only the possibility of issues with the formation of GABA but also potentially (and partially) accounting for the 'build up' of glutamate thereby unsettling that delicate excitatory/inhibitory balance. That's my take on it anyway. The body of research published so far suggests:

• GAD production (the isoforms GAD65 and GAD67) might not be optimal in cases of autism. Yip and colleagues*** noted reduced mRNA levels of GAD67 in Purkinje cells of a group with autism (Purkinje cells being a target for previous autism research based on the suggested involvement of cerebellar function). The same group also reported reduced mRNA levels of GAD65**** (here full-text).
• Overall, genomic studies which have included the examination of genes thought to be involved in the production of GAD have not yielded any wider significant issues in cases of autism as per the studies by Rabionet and colleagues***** and Buttenschøn and colleagues******.
• Environment has however been proposed as a possible interfering variable affecting GAD production and function as per the suggestion by Nouel and colleagues******* on the prenatal effects of a bacterial endotoxin on GAD67 (in rats). That and the possibility of autoantibodies to GAD65 being found in a small sub-group of children with autism and ADHD as reported by Rout and colleagues******** (similar antibody findings also being reported in the very interestingly named 'Stiff-Person syndrome', a condition characterised by amongst other things heightened sensitivity to stimuli).

I think you can see that for some people on the autism spectrum, GABA, it's receptors and findings around its manufacture - seems to have a few potential issues attached. Stepping back to the PLP / vitamin B6 link with GABA, there is also some interesting evidence emerging there also with autism in mind. Indeed another familiar name, Jim Adams (he of the vitamin RCT among other things) published a paper********* a few years back indicating high levels of plasma vitamin B6 to be present in cases of autism. You're probably thinking to yourself, well high levels of vitamin B6 is good? Er, not exactly, because high levels of vitamin B6 in unsupplemented individuals as this group were, might actually suggest that vitamin B6 is not being optimally metabolised by pyridoxal kinase into PLP for example. I could start to talk about pyridoxal kinase and ATP complexed to zinc (see here) but then we start asking questions about zinc availability and the whole thing gets really, really complicated.


I think I'll stop there for now with the hope that I have done more informing rather than misinforming. To end, a link to something completely different... The Killers and Mr Brightside.


GABA, Dabba, Doo!

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* Kang JQ. & Barnes G. A Common Susceptibility Factor of Both Autism and Epilepsy: Functional Deficiency of GABA(A) Receptors. JADD. May 2012.

** Ma DQ. et al. Identification of significant association and gene-gene interaction of GABA receptor subunit genes in autism. American Journal of Human Genetics. 2005; 77: 377-388.

*** Yip J. et al. Decreased GAD67 mRNA levels in cerebellar Purkinje cells in autism: pathophysiological implications. Acta Neuropathologica. 2007; 113: 559-568.

**** Yip J. et al. Decreased GAD65 mRNA levels in select subpopulations of neurons in the cerebellar dentate nuclei in autism: an in situ hybridization study. Autism Research. 2009; 2: 50-59.

***** Rabionet R. et al. Analysis of the autism chromosome 2 linkage region: GAD1 and other candidate genes. Neuroscience Letters. 2004; 372: 209-214.

****** Buttenschøn HN. et al. A population-based association study of glutamate decarboxylase 1 as a candidate gene for autism. The Journal of Neurotransmission. 2009; 116: 381-388.

******* Nouel D. et al. Prenatal exposure to bacterial endotoxin reduces the number of GAD67- and reelin-immunoreactive neurons in the hippocampus of rat offspring. European Neuropsychopharmacology. 2012; 22: 300-307.

******** Rout UK. et al. Presence of GAD65 autoantibodies in the serum of children with autism or ADHD. European Child & Adolescent Psychiatry. 2012; 21: 141-147.

********* Adams JB. et al. Abnormally high plasma levels of vitamin B6 in children with autism not taking supplements compared to controls not taking supplements. Journal of Alternative & Complementary Medicine. 2006; 12: 59-63.

Mouse modeling, immune function and autism

Contrary to the title of this post and any images that it may conjure up of mice parading down a runway in this season's 'hottest looks' whilst pouting to the clicks and flashes of multiple cameras, I'm back to mouse models and autism again(!) and an interesting piece of research by Hsiao and colleagues*.

I am kinda standing on the shoulders of giants with this paper given that it comes from the laboratory of Paul Patterson who has already run with a short description about it on his blog (see here). Whilst not pinning my colours to any mast, Prof. Patterson's blog is one I enjoy reading, not least because of the various links being made between the immune system and the brain (at least in mice). I assume most people would recognise by now that the brain does not run independent of the rest of the body despite our implicit need to compartmentalise anything and everything (see this post on labels).

Drawing heavily on Prof. Patterson's latest blog entry and the paper in question - hopefully without plagiarising - a few factoids:

• The Patterson team have previously published results based on a mouse model of stimulated immune activation during pregnancy and the resultant behavioural effects on offspring which seemed to overlap with the core symptoms of autism (see this paper by Malkova and colleagues**).
• In the latest study* the authors report on the profile of immune function in offspring mice of immune-stimulated mothers, suggesting some interesting effects in the area of T regulatory cells and cytokine production. I have recently talked about T-cells in this post on pristine cysteine so will perhaps put that to one side for now. Of just as much interest are elevations in that old favourite IL-6 and similar suggestions for IL-17, again the source of some interest recently on the topic of autoimmunity and autism (here). Roads toward inflammation seemed to be a key part of their findings.
• Coincidental to these findings is the report of "altered myeloid lineage potential and differentiation" in offspring. I'm not even going to profess to begin to know what this actually means, aside from referring you to quite a nice overview of hematopoietic stem cells (here) showing the distinction between myeloid and lymphoid progenitors. 
• Then to the big findings and please don't shoot the messenger: irradiating and transplanting "immunologically normal" bone marrow from both affected and non-affected control mice offspring into the offspring of immune stimulated mother mice seemed to correct some of the autism-type behaviours that were exhibited. So repetitive- and anxiety-like behaviours seemed to be reduced bearing in mind that anxiety is not (yet) a core symptom of autism (see here).
• That and some suggestion that timing might be everything when it comes to programming for immune dysfunction as a result of very few effects being seen when transplanting bone marrow from affected offspring to non-affected offspring over being born into a stimulated maternal immune system environment.

I note that on quite a few sites analysing these latest results, the authors have gone to great lengths to stress that (a) these were mouse findings - I'll say again, these were mouse findings, and (b) at the moment, no-one is suggesting that a bone marrow / stem cell transplant is any kind of 'treatment' for autism given questions for example, about whether the 'irradiation' bit of the procedure might have shown any effect alongside the actual bone marrow transplant. I would most definitely support these statements given both the preliminary nature of this research and also the complications and risks attached to bone marrow transplants (see here).

Having said that this is not the first time that bone marrow transplants and conditions like autism have appeared in the research literature. This paper by Akaho and colleagues*** talks about such transplants in cases of autism (and schizophrenia) occurring alongside leukaemia with a specific focus on maintaining treatment regimes and the anxiety related to the treatment process. Sharma and colleagues**** discussed some rather more direct observations following administration of "autologous bone marrow-derived mononuclear cells" in their quite varied patient group including cases of autism, bearing in mind one tree does not a forest make.

Indeed the concept of stem cell therapy, words which still seem to create quite an emotional response in many people, seems to be occurring more and more often in the research literature on autism as per this review by Siniscalco and colleagues***** (full-text) including a familiar name (Anna Sapone). I know many people might read 'stem cells and autism' and think back to those pop-up ads that seem to appear on various search engines offering some kind of James Bond style 'Die Another Day' rearrangement. Again, no endorsement is intended or given but perhaps what the Patterson lab study is suggesting is that a little more focused research is required in this area just before the door is entirely slammed shut. 

The Hsiao findings do represent another very important preliminary step into the immune-behaviour relationship with conditions like autism in mind. Assuming that the whole is greater than the sum of its parts, these moves towards a more whole body analysis of conditions like autism, where immune function, gut and gut bacterial function and brain function are examined in unison, offer the promise of some truly tantalising insights into autism.

And finally... just in case you are not convinced on the potential for an immune-behaviour link, cast your eye over this recent preliminary report on Alzheimer's disease and the use of IVIg as another area ripe for further inquiry.

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* Hsaio EY. et al. Modeling an autism risk factor in mice leads to permanent immune dysregulation. PNAS. July 2012.
DOI: 10.1073/pnas.1202556109

** Malkova NV. et al. Maternal immune activation yields offspring displaying mouse versions of the three core symptoms of autism. Brain, Behavior & Immunity. 2012; 26: 607-616.

*** Akaho R. et al. Bone marrow transplantation in subjects with mental disorders. Psychiatry & Clinical Neurosciences. 2003; 57: 311-315.

**** Sharma A. et al. Administration of autologous bone marrow-derived mononuclear cells in children with incurable neurological disorders and injury is safe and improves their quality of life. Cell Transplantation. 2012; 21: Suppl 1: S79-S90.

***** Siniscalco D. et al. Autism spectrum disorders: is mesenchymal stem cell personalized therapy the future? Journal of Biomedicine & Biotechnology. 2012; 480289.

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Hsiao EY, McBride SW, Chow J, Mazmanian SK, & Patterson PH (2012). Modeling an autism risk factor in mice leads to permanent immune dysregulation. Proceedings of the National Academy of Sciences of the United States of America PMID: 22802640