We selected a subset of four individuals from a multigenerational kindred, Family-811 with bipolar disorder originally described by Gershon and colleague42 (Fig. 1A). This subset, referred to here as the “Family-811 quartet”, consisted of an unaffected father (GM08330) and mother (GM08329) and their two sons with BD (GM05225 and GM05224) (Fig. 1A; Sup. Table 1). Whole-genome SNP profiling of 733,202 markers was performed on fibroblast DNA. Analysis of these data using inheritance by descent measures confirmed the expected parent-child and sibling relationships of the Family-811 quartet (Fig. 1B; Sup. Table 2), and using multi-dimensional scaling analysis showed that the quartet clusters with the Northern and Western Europe (CEU) individuals from HapMap (Fig. 1C).
