For candidate genes of monoamine neurotransmission (SLC6A4, TPH2, COMT, MAOA ,DRD1-DRD5), among 5225 participants from the Northern Finland Birth Cohort 1966, there was a significant SNP-by-sex interaction on depression for a variant on chromosome 11q23 (DRD2) [48]. The gene discussed is SLC6A4; the disease is major depressive disorder.