Association Study Between Polymorphism Of Catechol-O-methyltransferase Gene And Attention Deficit Hyperactivity Disorder, Cognitive Function Of Attention Deficit Hyperactivity Disorder

ObjectivesTo study the cognitive function profiles in children with ADHD. To explore the relationship between rs4680 and rs6267 polymorphism of COMT genes and attention deficit hyperactivity disorder (ADHD).Methods114 patients with ADHD and 76 normal controls in Hunan area were involved. We used some neuropsychological tests, including Stroop Word Color Test, Continuous Performance Task (CPT) and Wisconsin Card Sorting Test (WCST) to evaluate the executive function. The significance for the association was estimated by analysis of variance.The rs4680 and rs6267 polymorphism of COMT genes in these patients and normal controls were examined with polymerase chain reaction and restriction fragment length polymorphism technique. The genotype and allele frequencies of each single nucleotide polymorphism (SNP) were compared between ADHD and normal controls. The relationship was examined between performances of neuropsychological tests and Child Behavior Checklist (CBCL) of ADHD and each SNP.ResultsCompared with control group, the total responses number, responses number on first categories, perseverative responses number of ADHD patients were higher than that of normal control in WCST (P<0.05 ) .But the categories control number, reflections on the correct time, incomplete categories number were lower than that of normal control in WCST (P< 0.01) .Word reading, color naming and the word-color interacting of ADHD patients were poorer than that of normal control in stroop test (P< 0.05) . Error number and omission number of ADHD patients were lower than that of normal control in CPT (P<0.01) .There was not difference between ADHD normal control in the genotype and allele frequencies of rs4680 and rs6267 polymorphism , no difference of genotype and allele frequencies in sex either (P>0.05 ) . The genotype and allele frequencies rs6267 polymorphism was different between predominantly hyperactive-impulsive type(ADHD-HI) and combined type(ADHD-C) (P<0.01) .The frequency of genotype G/G and allele G in ADHD-HI were significantly higher than that of ADHD-C.The rs4680 polymorphism was associated with percentage of conceptual level in ADHD patients (P<0.01) , the frequency of genotype A/A was more than others. The rs6267 polymorphism was associated with thinking problem and disciplinary problems of CBCL (P<0.05) ,the frequency of genotype G/G was more than G/T.ConclusionsThe obvious impaired executive functions were found in children with ADHD, but no association was found between the COMT gene and ADHD. However, there might be association between rs6267 polymorphism and some clinical character or subtype of ADHD. The association was found between rs4680 polymorphism and some cognitive function of ADHD too.