R347C Polymorphisms in ADRA1A Genes and Mirtazapine Treatment Response in Koreans with Major Depression

Abstract

Objectives:Adrenergic alpha 1 and 2 receptors work as pathways to control the serotonergic neuron moderation and mirtazapine acts as antagonist of these receptors. The adrenoreceptor alpha 1a (ADRA1A) gene, which encodes adrenergic alpha 1 receptor, has Arg- 347Cys genetic polymorphism and the polymorphism has strong relationship with many neuro-psychiatric diseases. In this study, we explored the relationship between ADRA1A R347C polymorphism and mirtazapine treatment response in Koreans with major depression. Methods:352 patients enrolled in this study, and the symptoms were evaluated by 17-item Hamilton Depression Rating (HAMD-17) scale. After 1, 2, 4, 8, and 12 weeks of mirtazapine treatment, the association between ADRA1A R347C polymorphism and remission/ response outcomes was evaluated. Results:Treatment response to mirtazapine was significantly better in T allele carriers than C allele homozygotes after 12 weeks of mirtazapine monotherapy. The percentile decline of HAMD-17 score in T allele carriers was larger than that of C allele homozygotes. ADRA1A R347C genotypes were not significantly associated with remission. Conclusions:The result showed that treatment response to mirtazapine was significantly associated with ADRA1A R347C genetic polymorphism. T allele carriers showed better treatment response than C allele homozygotes. It can be supposed that T allele carriers have a trend of better treatment response to mirtazapine monotherapy.