title: Family-based and case-control association studies of catechol-O-methyltransferase in attention deficit hyperactivity disorder suggest genetic sexual dimorphism.
abstract: Attention deficit hyperactivity disorder (ADHD) is the most common childhood-onset behavioral disorder. Boys are more often affected than girls. Family, twin, and adoption studies have supported a strong genetic basis. Some studies show that a catechol-O-methyltransferase (COMT) polymorphism affecting enzyme activity was associated with personality characteristics and diseases, such as novelty-seeking personality, substance abuse, and heroin addiction, whose features are similar to ADHD or are associated with ADHD. These findings suggest that the COMT gene may be a candidate gene for ADHD. TDT, HHRR, and case-control association studies were conducted within a sample of 202 nuclear ADHD families, 340 ADHD cases, and 226 controls in the Han Chinese population. Diagnoses and ADHD subtypes were ascertained according to DSM-IV criteria using American Clinical Diagnostic Interviewing Scales. The HHRR analysis suggested that the low enzyme-activity COMT Met allele was preferentially transmitted to ADHD boys (160 trios, chi(2) = 3.858, P = 0.05, df = 1) but not girls. This association is particularly pronounced among male ADHD probands without any comorbidity (50 trios, HHRR: chi(2) = 5.128, P = 0.024, df = 1; TDT: chi(2) = 4.558, P = 0.033, df = 1), especially the ADHD-I subtype (32 trios, HHRR: chi(2) = 5.792, P = 0.016, df = 1; TDT: chi(2) = 5.333, P = 0.021, df = 1). The case-control study revealed that the Val allele was more frequent in females meeting ICD-10 or DSM-IV criteria for ADHD than in female controls (86 and 79.5%, respectively, chi(2) = 4.059, P = 0.044, df = 1). Although these results suggest the COMT gene exerts some influence on the risk for ADHD in the Han Chinese population, given the potential for Type I error, these findings require replication before drawing definitive conclusions.
authors.affiliation: Institute of Mental Health, Peking University, Beijing 100083, People's Republic of China.
authors.forename: Qiujin
authors.initials: Q
authors.lastname: Qian
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Rulun
authors.initials: R
authors.lastname: Zhou
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Stephen
authors.initials: S
authors.lastname: Glatt
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Faraone
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000201:enzymology / Q000235:genetics*; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D016009:Chi-Square Distribution; D002648:Child; D004247:DNA / Q000235:genetics; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008715:Methionine / Q000235:genetics; D020125:Mutation, Missense; D009679:Nuclear Family; D010641:Phenotype; D011110:Polymorphism, Genetic; D012737:Sex Factors; D014633:Valine / Q000235:genetics
chemical_list: D004247:DNA; D008715:Methionine; D002394:Catechol O-Methyltransferase; D014633:Valine