Autosomal recessive retinitis pigmentosa and Coats disease: a presumed familial incidence.

Three of four siblings of normal parents had a combination of Coats disease and retinitis pigmentosa bilaterally. Our report of their respective cases is, to our knowledge, the first report of a familial incidence of the combination of the two diseases in an individual and supports the implication that Coats disease may be a genetic abnormality. The pathological process was essentially the same in all three patients, although it occurred differently in one of the three siblings and gave rise to an altered functional and clinical picture. The similarities may indicate that the convenient categories of "tapeto-retinal degenerations" are clinical variations of the same genetic abnormality.