Familial disease of the renal medulla. A study of progeny in a family with medullary cystic disease.

Cystic disease of the renal medulla is rarely diagnosed before end-stage renal failure appears. To discover early signs of disease in an affected family, we studied renal function and intravenous pyelography in 12 asymptomatic children of three sisters with this disorder. Defects in urine concentrating ability and X-ray abnormalities indistinguishable from medullary sponge kidney were found. While these changes probably represent early manifestations of medullary cystic disease, a clear separation between medullary cystic disease and medullary sponge kidney cannot be made in our patients. We propose that the designation "familial disease of the renal medulla" be used for such patients, with further classification determined by evidence of progressive disease.