Cosegregation of bipolar disorder and autosomal-dominant medullary cystic kidney disease in a large family.

OBJECTIVE The authors report a large family in which bipolar disorder appears to cosegregate with autosomal-dominant medullary cystic kidney disease. METHOD Information regarding diagnostic criteria for bipolar disorder and medullary cystic kidney disease were gathered from family members through formal research interviews, hospital admission records, imaging reports, and laboratory data. RESULTS Of the seven members with medullary cystic kidney disease, five had bipolar I disorder, one had unipolar depression, and one had a hyperthymic phenotype. Information was not available on two members. CONCLUSIONS The cosegregation in this family suggests a close proximity between genes for the two disorders. The two known loci of medullary cystic kidney disease are in regions of chromosomes 1 and 16 that have been previously linked to bipolar disorder and schizophrenia. This family may be a useful resource for positional cloning of bipolar candidate genes.