Mesangiocapillary glomerulonephritis in Down's syndrome.

The clinical and pathologic features of progressive renal disease in 4 patients with Down's syndrome are described. All patients were male, between 20 and 30 years of age at the time of clinical presentation. Three out of 4 had proteinuria, and 2 had hematuria. Serologic tests for hepatitis B virus infection and antinuclear antibodies performed in 2 patients were negative. Examination of renal tissue from biopsy and/or from autopsy revealed mesangiocapillary glomerulonephritis (MCGN), type 1. While an increased incidence of congenital heart disease and acute leukemias has been documented in Down's syndrome, an association with MCGN has not been reported previously to our knowledge. This probably represents a form of idiopathic MCGN and may be related to the long survival of these individuals.