Monday, 24 March 2014

A specific female ASD phenotype is emerging...

The title of this brief post is a quote taken from the abstract of the paper by Frazier and colleagues [1] who, following an analysis of participants included in the Simons Simplex Collection, concluded that autism research and practice might well consider looking at differences in the presentation of autism spectrum disorders (ASDs) between the sexes.
The Lady of Shalott @ Wikipedia 

Including nearly 2500 people with autism including over 2100 males and 304 females, examining "autism symptoms, cognitive and motor functioning, adaptive behavior, and associated behavior problems", researchers were able to build up a quite generalised picture of symptom presentation across the sexes.

Bearing in mind their assertion that "diagnostic instruments captured autism similarly in males and females" they reported some interesting trends: "Females with ASD had greater social communication impairment, lower levels of restricted interests, lower cognitive ability, weaker adaptive skills, and greater externalizing problems relative to males".

Of course we have been here before as per a previous blogpost on this topic albeit not exactly with the same profiles being reported. Compared with the results from Mandy and colleagues [2] for example, the finding of less frequent issues with repetitive stereotyped behaviour in girls seems to be one of the few consistencies reported [3] again and again [4] provided we assume that restricted interests and repetitive behaviours fall into the same behavioural domain. Bear in mind also that Mandy et al were looking at a participant group comprising "high-functioning ASD" so I'm perhaps comparing apples and pears. The results from Head and colleagues [5] (open-access) however do suggest there is more to do in this area with their assertion that: "females with ASD have more developed social skills than males with ASD".

Frazier et al conclude by suggesting that the disparity in cases of autism according to gender may very well, to some extent, be due to some of those sex differences in behavioural presentation and the need to "evaluate whether observed sex ratios in high-functioning cases are reduced if female-specific indicators of restricted interests are included". Certainly with the arrival of DSM-5 and all that SCD (social communication disorder) chatter, it will be interesting to see the data on which sex is more likely to be diagnosed with autism, and which with SCD. Oh, and then there are the results from Sébastien Jacquemont and colleagues [6] and the female protective model (see here) ...

To close, no song this time around but rather a link to a forgotten classic animated film: The Lord of the Rings which is currently doing the rounds among the female members of my brood. Indeed, I am very proud to say that Barbie and dolls and related stuff has given way to discussions about the finer points of Tolkien's classic books. And the primary influence behind this shift in interests? The Lego DS game... who said technology was all doom and gloom for child development?

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[1] Frazier TW. et al. Behavioral and cognitive characteristics of females and males with autism in the simons simplex collection. J Am Acad Child Adolesc Psychiatry. 2014 Mar;53(3):329-340.e3.

[2] Mandy W. et al. Sex differences in autism spectrum disorder: evidence from a large sample of children and adolescents. J Autism Dev Disord. 2012 Jul;42(7):1304-13.

[3] Werling DM. & Geschwind DH. Sex differences in autism spectrum disorders. Curr Opin Neurol. 2013 Apr;26(2):146-53.

[4] Kreiser NL. & White SW. ASD in Females: Are We Overstating the Gender Difference in Diagnosis? Clin Child Family Psych Rev. 2014; 17: 67-84.

[5] Head AM. et al. Gender differences in emotionality and sociability in children with autism spectrum disorders. Molecular Autism 2014, 5:19

[6] Jacquemont S. et al. A Higher Mutational Burden in Females Supports a “Female Protective Model” in Neurodevelopmental Disorders. Am J Human Genetics. 2014. February 27.

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ResearchBlogging.org Frazier TW, Georgiades S, Bishop SL, & Hardan AY (2014). Behavioral and cognitive characteristics of females and males with autism in the simons simplex collection. Journal of the American Academy of Child and Adolescent Psychiatry, 53 (3), 329-340000 PMID: 24565360