Current status of genetic study on affective disorder

A series of studies have indicated the existence of genetic predisposition and the polygenic-multifactorial mode of transmission for bipolar disorder(BPD). Linkage studies have defined several BPD susceptibility loci. The findings to date suggested the candidate regions on 4p16, 12q23-24, 18p11, 18q22, 21q22, Xq24-27 for BPD, although no genes has yet been definitively identified. There are also many reports on the analyses of candidate genes, using association studies. But none of gene polymorphisms have been established as firm disease alleles with sufficient replications. Novel statistical methods and development of new strategies are necessary to approach the goal of isolating susceptibility genes.