Initial report of a genome search for the affective disorder predisposition gene in the old order Amish pedigrees: chromosomes 1 and 11.

Family data have suggested that some forms of major affective disorder are genetic. Certain of the Old Order Amish pedigrees have a familial form of the disease. In this report we present the results of genetic analyses under autosomal dominant mode of transmission with reduced penetrance and three different disease hierarchies. The pedigrees were genotyped with 28 markers from chromosome 1 and 23 markers from chromosomes 11. None of the markers result in a significantly positive lod score.