Hereditary nephronophthisis with a life span of three decades. Light and electron microscopical, immunohistochemical, clinical and family studies.

Familial nephronophthisis was diagnosed in a son and two daughters of a mother who herself died in uraemia at the age of 29 years. The son died at 33 years, two daughters are alive at 30 and 33 years. Our cases suggest a dominant autosomal type of inheritance because the mother married twice; the affected son was from the first marriage and the affected daughters from the second marriage. There was no known consanguinity between the parents. The pathogenesis of the disease can be explained by a slowly progressive process that leads to complete or partial obstruction of the tubules in the corticomedullary area, and also, therefore, to cystic dilatations. Histological evidence for this is provided by the proliferation of fibroblasts around the collecting ducts and other tubules, prominent thickening of the tubular basement membrane, and fibroblasts and collagen fibrils in or inside the thickened basement membranes. An ultrastructural description of affected kidneys is given.