Association of autism severity with a monoamine oxidase A functional polymorphism Journal Articles uri icon

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  • 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.


  • Cohen, IL
  • Liu, X
  • Schutz, C
  • White, Bradley
  • Jenkins, EC
  • Brown, WT
  • Holden, JJA

publication date

  • September 2003

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