Familial IgA nephropathy: report of two cases and brief review of the literature.

Immunoglobulin A nephropathy developed in two siblings who shared the DRw4 antigen but who were otherwise HLA-A, -B, and -C unrelated. It is suggested that a genetically induced alteration in the immune response can cause some of the cases of mesangial IgA glomerulopathy and that close blood reltaives of patients with this disease should be checked for the possible existence of renal abnormalities.