Association study on the NAPG gene and bipolar disorder in the Chinese Han population.

Bipolar disorder is a mental health problem throughout the world. Chromosome 18p11 has been identified by several studies as a susceptiblilty region for bipolar disorder and NAPG, located on 18p11, has been suggested as being associated with bipolar disorder in European population. Our study employed five SNPs (rs2290279, rs495484, rs510110, rs617040 and rs473938) to investigate the role of NAPG in the Chinese Han population based on a sample of 465 controls vs. 499 bipolar patients. Rs617040 was excluded from further analysis because of deviation from Hardy-Weinberg equilibrium. Rs473938 and rs2290279 showed significant association in both allele and genotype frequencies (rs473938: allele p=0.0028 after 100,000 permutations, genotype p=0.0018; rs2290279: allele p=0.0042 after 100,000 permutations, genotype p=0.0028). Several combinations of haplotype were found to be associated with bipolar disorder. Haplotype T-A-T of rs473938-rs2290279-rs495484 was defined by confidence intervals algorithm and had a p value of 0.0038 after 100,000 permutations. Our study supports NAPG as a candidate for susceptibility to bipolar disorder.