Association of autism severity with a monoamine oxidase A functional polymorphism

Authors


Ira L. Cohen, PhD, Behavioral Assessment & Research Laboratory, Department of Psychology, NYS Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York, NY 10314, USA.
Tel.: 718-494-5181;
fax: 718-494-5395;
e-mail: Ira.Cohen@omr.state.ny.us

Abstract

A functional polymorphism (the upstream variable-number tandem repeat region, or uVNTR) in the monoamine oxidase A (MAOA) promoter region has been reported to be associated with behavioral abnormalities as well as increased serotonergic responsivity. We examined the relation between MAOA-uVNTR alleles and the phenotypic expression of autism in 41 males younger than 12.6 years of age. Children with the low-activity MAOA allele had both lower intelligence quotients (IQ) and more severe autistic behavior than children with the high-activity allele. In follow-up testing of 34 of the males at the 1-year time-point, those with the low-activity allele showed a worsening in IQ but no change in the severity of their autistic behavior. We conclude that functional MAOA-uVNTR alleles may act as a genetic modifier of the severity of autism in males.

Ancillary