ABSTRACT
OBJECTIVES: The aim of this study was to examine the association of the ADRA2A MspI and DraI polymorphisms with methylphenidate (MPH) response in Korean children with ADHD. METHODS: The present study included 112 children and adolescents with ADHD (mean age=9.1+/-2.1 years), consisting of 92 boys (82.1%) and 20 girls (17.9%). ADHD was diagnosed based on the DSM-IV criteria using the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). For the clinical evaluation of the ADHD subjects, the ADHD Rating Scale-IV (ADHD-RS) and Clinical Global Impression (CGI) were administered at baseline and 8 weeks after MPH treatment. ADRA2A MspI and DraI polymorphisms were genotyped. The chi2 test was used to evaluate the relationship between the ADRA2A genotype and the response to MPH. The correlation between the genotype of ADRA2A and the change in the ADHD-RS scores after MPH treatment was assessed using the analysis of variance test and t-test. The significance level was set at p=0.01. RESULTS: No significant association was found between the genotypes of the ADRA2A MspI or DraI polymorphisms and MPH treatment response according to the CGI-improvement score (p>0.05). Comparing the changes in ARS scores after MPH treatment according to the genotypes of the MspI or DraI polymorphisms, we found no significant differences between subjects with different genotypes (p>0.05). CONCLUSION: Our results do not support the significant association between the MspI genotype and MPH response in Korean ADHD subjects, which was previously reported. In addition, we document no evidence of association between the DraI polymorphism and MPH treatment response in the Korean ADHD population.