title: Association analyses of MAOA in Chinese Han subjects with attention-deficit/hyperactivity disorder: family-based association test, case-control study, and quantitative traits of impulsivity.
abstract: Monoamine oxidase A (MAOA) plays a critical role in the metabolism of monoamine neurotransmitters including serotonin (5-HT), norepinephrine (NE), and dopamine (DA). Genetic studies have found an association between MAOA and attention-deficit/hyperactivity disorder (ADHD), especially impulsivity. However, there has been inconsistency among studies which may be due to the complexity and heterogeneity of ADHD, including its sexual dimorphism and the presence of several subtypes. We conducted transmission disequilibrium tests (TDTs) in 1,253 trios and found no association between five single nucleotide polymorphisms (SNPs) of MAOA with ADHD in general or in the predominantly inattentive (ADHD-I) or combined types (ADHD-C), but with the predominantly hyperactive/impulsivity type (ADHD-HI). The association with MAOA was restricted to males, especially males with ADHD-HI. Logistic regression analyses of data from 1,824 cases and 957 controls did not indicate any association. We used analysis of covariance to analyze the association between MAOA genotype with the "inhibit" factor of the Behavior Rating Inventory of Executive Function (BRIEF) in 640 probands and performance on the Stroop test in 810 probands. Probands homozygous for risk alleles found in the TDT test had higher "inhibit" scores on the BRIEF scale which represents more severe impulsivity; this results also was restricted to males. No association was found with Stroop test performance. In conclusion, our results provide some evidence that MAOA may be associated with the ADHD-HI subtype and support the association between MAOA and impulsivity, which may be a potential endophenotype of ADHD. However, the results were strongly influenced by gender.
authors.affiliation: Institute of Mental Health, Peking University, Beijing, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Guan
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.forename: Ning
authors.initials: N
authors.lastname: Ji
authors.forename: Hai-Mei
authors.initials: HM
authors.lastname: Li
authors.forename: Ze-Hua
authors.initials: ZH
authors.lastname: Li
authors.forename: Qiu-Jin
authors.initials: QJ
authors.lastname: Qian
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Glatt
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Faraone
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002681:China; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007175:Impulsive Behavior / Q000235:genetics*; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics*; D018377:Neurotransmitter Agents / Q000378:metabolism; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D057190:Stroop Test
chemical_list: D018377:Neurotransmitter Agents; D008995:Monoamine Oxidase