RESUMO
OBJECTIVE: Attention deficit hyperactivity disorder is known to be a disorder with high genetic trait. Recently the relationship between alleles frequency distribution and ADHD, has been actively researched. In Korea, the relationship between the genetic type and alleles for COMT (Catechol-O-methyltransferase) gene, has been studied in ADHD patients. METHODS: Thirty three patients diagnosed with ADHD according to the DSM-IV diagnostic criteria were selected for the study. The diagnosis and clinical features were confirmed by Korean version Child behavior check list, Korean version Conner's parent rating scale, Attention deficit Diagnostic System, Korean version Spielberger state-trait anxiety scale etc. For the control group, the parents of patients were chosen. Blood samples were taken from the 99 subjects. DNA was extracted from blood lymphocytes, PCR was performed for COMT NlaIII VNTR Polymorphism. Allele and genotype frequencies were compared using the Chi-square test. For the family-based analyses, we used the TDT and HHRR method. RESULTS AND CONCLUSION: In comparing the ADHD transmitted group and the not transmitted group, No significant difference was seen between the COMT genetic type and alleles distribution. As a result, it is viewed that there is not relationship between ADHD and the dopamine transporter gene, but final decision is indefinite. Follow up studies with larger patient or pure subgroups are expected.