Association Between Monoamine Oxidase Gene Polymorphisms and Attention Deficit Hyperactivity Disorder in Korean Children

Abstract

Attention deficit hyperactivity disorder (ADHD) is a common disorder of the school-age population. ADHD is familial and genetic studies estimate heritability at 80-90%. The aim of the present study was to investigate the association between the genetic type and alleles for the monoamine oxidase (MAO) gene in Korean children with ADHD. The sample consisted of 180 ADHD children and 159 control children. We diagnosed ADHD according to DSM-IV. ADHD symptoms were evaluated with Conners' Parent Rating Scales and Dupaul Parent ADHD Rating Scales. Blood samples were taken from the 339 subjects, DNA was extracted from blood lymphocytes, and polymerase chain reaction was performed for MAO polymorphism. Allele and genotype frequencies were compared using the chi-square test. We compared the allele and genotype frequencies of MAO gene polymorphism in the ADHD and control groups. This study showed that there was a significant correlation among the frequencies of the rs5906883 (odds ratio [OR] = 1.47, 95% confidence interval [CI] = 1.08-2.00, p = 0.014) and the rs3027407 (OR = 1.41, 95% CI = 1.03-1.91, p = 0.029) alleles of MAO, but the final conclusions are not definite. Follow-up studies with larger patient or pure subgroups are expected. These results suggested that MAO might be related to ADHD symptoms.

Association of Monoamine Oxidase A (MAOA) Gene uVNTR and rs6323 Polymorphisms with Attention Deficit and Hyperactivity Disorder in Korean Children

“…We analyzed a total of 472 samples from the Children’s Health and Environmental Research (CHEER) cohort study and a previous study described in [ 32 ]. Of these samples, 120 ADHD children, 322 control individuals were a subset of the CHEER cohort study and 30 ADHD children were a subset of the samples analyzed in Kwon et al (2014).…”

“…The Bonferroni correction was applied to adjust the α-level according to the number of markers (<0.05/2 = 0.025). It has been reported that approximately 210 subjects are needed to obtain a 95% sample power in a case-control study of ADHD in the Korean population [ 32 ]. In this study, we expected that there was sufficient power to evaluate the effects between the MAOA gene polymorphisms and ADHD.…”

ADHD co-morbidities: A review of implication of gene × environment effects with dopamine-related genes

“…Rs6323, a number of other SNPs, and uVNTR have been associated with ADHD in haplotype analyses, with the MAOA-L alleles and rs6323 G-allele contributing to the risk (Domschke et al, 2005;Hwang et al, 2018;Xu et al, 2007;Faraone and Mick, 2010;Kwon et al, 2014;Rommelse et al, 2008). For example, in an Indian population, the risk alleles of several SNPs in the MAOA gene, including the G allele of the rs6323 polymorphism, and uVNTR MAOA-L allele in haplotype with rs6323, were preferentially transmitted from mothers to ADHD probands, this was detected only in male probands, and was suggested by the author as one of the possible reasons for higher ADHD prevalence in males.…”