Clinical, pathological and genetic aspects of a form of cystic disease of the renal medulla: familial juvenile nephronophthisis (FJN).

A combined clinical, pathological and genetic study of 13 cases of FJN is reported. The clinical features are conistent with those described in the literature, except that short stature is not a feature in this group. Hyperplasia of the juxtaglomerular apparatus has been seen in 5 of 9 cases where histology was done. The genetic studies support the view that FJN is an autosomal recessive hereditary disease. Because their patterns of inheritance differ, FJN and medullary cystic disease (MCD) are separate entities. We suggest simplification of the nomenclature to: medullary cystic disease of childhood type, formerly FJN and medullary cystic disease of adult type, formerly MCD.