Asperger's Syndrome Research Today is a free monthly online journal that collates and summarizes the latest research about Asperger's Syndrome, including details on symptoms, diagnosis, treatment, medication.

Differences in finger length ratio between males with autism, pervasive developmental disorder-not otherwise specified, ADHD, and anxiety disorders.

de Bruin EI, Verheij F, Wiegman T, Ferdinand RF

Department of Child and Adolescent Psychiatry, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, the Netherlands.

Children with autism have a relatively shorter index finger (2D) compared with their ring finger (4D). It is often presumed that the 2D:4D ratio is associated with fetal testosterone levels and that high fetal testosterone levels could play a role in the aetiology of autism. It is unknown whether this effect is specific to autism. In this study, 2D:4D ratios of 144 males aged 6 to 14 years (mean age 9y 1 mo [SD 1y 11 mo]) with psychiatric disorders were compared with those of 96 males aged 6 to 13 years from the general population (mean age 9y 1 mo [SD 1y 10 mo]). Psychiatric disorders were divided into autism/Asperger syndrome (n=24), pervasive developmental disorder-not otherwise specified (PDD-NOS; n=26), attention-deficit-hyperactivity disorder (ADHD)/oppositional defiant disorder (ODD; n=68), and anxiety disorders (n=26). Males with autism/Asperger syndrome (p<0.05) and ADHD/ODD (p<0.05) had significantly lower (though not significantly; p=0.52) ratios than males with an anxiety disorder, and males with autism/Asperger syndrome had lower ratios than those in the comparison group. These results indicated that higher fetal testosterone levels may play a role, not only in the origin of autism, but also in the aetiology of PDD-NOS and of ADHD/ODD. Males with anxiety disorders might have been exposed to lower prenatal testosterone levels.

Published 19 November 2006 in Dev Med Child Neurol, 48(12): 962-5.
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