We previously conducted a family-based association study of dopamine transporter gene (SLC6A3) in 170 affected offspring trios defined by a child (12.9 ± 5.3 years of age) with DSM-IV Bipolar-I disorder and found a positive association with one HapMap SNP (rs40184) that survived correction for multiple statistical comparisons (p = 0.038) [40]. Here, SLC6A3 is linked to bipolar I disorder.