HLA typing and a range of autoantibodies were evaluated in five families affected with type A renal glycosuria. HLA typing demonstrates that this inherited disease is controlled by an autosomal dominant gene located on chromosome six in close genetic linkage with the HLA complex. All affected family members have significant titres of autoantibodies to nuclear antigens, native DNA, smooth muscle, mitochondria, liver antigens, thyroglobulin, thyroid microsomes and renal tubule brush border with variable association. This suggests that renal glycosuria is a complex HLA-linked disease with increased susceptibility to multiple autoantibody production and this urges caution with respect to its classical definition as a benign condition.