ASSOCIATION BETWEEN THE TRYPTOPHAN-HYDROXYLASE GENE AND MANIC-DEPRESSIVE ILLNESS

Background: Genes encoding proteins involved in serotonergic metabolis m are major candidates in association studies of mood disorders and su icidal behavior. This association study explores whether the tryptopha n hydroxylase (TPH) gene, which codes for the rate-limiting enzyme of serotonin biosynthesis, is a susceptibility factor for manic-depressiv e illness, with or without a history of suicide attempts. Methods: The TPH intron 7 A218C polymorphism was determined using a polymerase cha in reaction-based method in DNA samples from 152 patients with bipolar disorder and 94 healthy control subjects. Results: There was a signif icant association between TPH genotypes and manic-depressive illness. Among patients with bipolar disorder, no association was found between TPH alleles and suicidal behavior. Conclusions: This result suggests the involvement of the TPH gene in susceptibility to manic-depressive illness. This preliminary result requires confirmation in further grou ps of patients and controls.