A pedigree series for mapping disease genes in bipolar affective disorder: sampling, assessment, and analytic considerations.

A series of 57 extended pedigrees with high density of bipolar affective disorder is described. Ascertainment and diagnostic procedures are documented and simulation studies to assess statistical power are carried out. The pedigrees, obtained in the US and Israel, are comprised of 1508 adult individuals with best estimate consensus diagnoses (12-71 relatives per pedigree), 490 of whom (including 401 sib pairs) meet criteria for a conservative disease definition (bipolar disorder or recurrent major depression). Cell lines have been established on 1324 of these individuals. Statistical power to detect linkage with lod score analysis, assuming autosomal dominant transmission and highly polymorphic DNA markers, is nearly 100% for alpha (proportion of linked families) = 30%, and 75% for alpha = 20%. This is the largest bipolar pedigree series reported to date; its unique features make it amenable to various gene detection techniques.