Family-based and association studies of monoamine oxidase A and attention deficit hyperactivity disorder (ADHD): preferential transmission of the long promoter-region repeat and its association with impaired performance on a continuous performance test (TOVA).

Abstract

Monoamine oxidase A (MAO A) is located on the X chromosome and metabolizes biogenic amines including dopamine, norepinephrine and serotonin. A functional promoter-region polymorphism of this gene has been described that has been studied in a number of mental illnesses but not in attention deficit hyperactivity disorder (ADHD). In the current study, we examined the MAO A promoter-region polymorphism initially in 133 triads and observed preferential transmission of the long alleles from 74 heterozygote mothers to ADHD probands (chi(2) = 4.37, P = 0.036, df = 1). We also examined the role of this polymorphism in a computerized continuous performance test, the TOVA. Significant differences were observed on errors of commission (chi(2) = 7.021, P = 0.008) and patients carrying the long MAO A allele made significantly more such errors. Errors of commission are a measure of impulsivity. However, following Ritalin (methylphenidate) administration the association between this polymorphism and errors of commission was markedly attenuated and no longer significant at the P < 0.05 level. We also analyzed the provisional association by the case-control design. A significant difference in allele frequency was observed between 110 male probands vs 202 male controls (Pearson chi(2) = 7.94, P = 0.047). Similarly results were obtained when 19 female probands were compared to female controls (genotype chi(2) = 21.28; P = 0.0032, 3 df and allele chi(2) = 30.88, P= 0.0007, 2 df). All three complementary approaches employed (family-based, case-control and quantitative trait design) suggest a role for the MAO A promoter-region polymorphism in conferring risk for ADHD in our patient population.

• Authors: I Manor, S Tyano, E Mel, J Eisenberg, R Bachner-Melman, M Kotler, R P Ebstein
• Journal: Molecular psychiatry (Mol Psychiatry) Vol. 7 Issue 6 Pg. 626-32 ( 2002) ISSN: 1359-4184 [Print] England
• PMID: 12140786 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA
• Monoamine Oxidase

Topics

• Attention Deficit Disorder with Hyperactivity (enzymology, genetics)
• Chromosomes, Human, X
• DNA (blood, genetics)
• Family
• Female
• Genetic Carrier Screening
• Genotype
• Humans
• Male
• Monoamine Oxidase (genetics)
• Polymorphism, Genetic
• Promoter Regions, Genetic
• Psychological Tests
• Repetitive Sequences, Nucleic Acid