In an association analysis between the polymorphism and bipolar disorder in a Japanese sample of 88 patients and 98 controls matched for age, sex, and ethnicity, the distribution of alleles did not differ significantly between the two groups. pGL3-promoter luciferase reporter vectors containing the polymorphic region increased luciferase activity relative to empty pGL3-promoter vector in HeLa, IMR-32 (neuroblastoma) and Hs683 (glioma) cell lines; however, no significant difference was detected between alleles for either cell line.