title: Differences in finger length ratio between males with autism, pervasive developmental disorder-not otherwise specified, ADHD, and anxiety disorders.
abstract: 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.
authors.affiliation: Department of Child and Adolescent Psychiatry, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, the Netherlands.
authors.forename: Esther I
authors.initials: EI
authors.lastname: de Bruin
authors.forename: Fop
authors.initials: F
authors.lastname: Verheij
authors.forename: T
authors.initials: T
authors.lastname: Wiegman
authors.forename: Robert F
authors.initials: RF
authors.lastname: Ferdinand
mesh_terms: D000293:Adolescent; D001008:Anxiety Disorders / Q000473:pathology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology*; D001321:Autistic Disorder / Q000473:pathology*; D001837:Body Weights and Measures; D016022:Case-Control Studies; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000473:pathology*; D005385:Fingers / Q000473:pathology*; D006801:Humans; D008297:Male