BACKGROUND A 60 member Turkish kindred with autosomal dominant hypertension, which cosegregates completely with brachydactyly and short stature, was studied. Affected people have severe hypertension and generally die of stroke by the age of 50. The hypertension closely resembles essential hypertension and, accordingly, the mechanisms of blood pressure elevation are unknown. The gene responsible was mapped to chromosome 12p. METHODS All 29 affected family members underwent a basic physical examination and funduscopy. Other than markedly elevated blood pressures and the residua of stroke in a few subjects, the apparent lack of end organ damage was striking, including the normal appearing fundi. Five affected individuals were studied in a clinical research unit study. All underwent a complete ophthalmological examination. Fluorescein angiograms were obtained in three subjects. RESULTS Systolic blood pressures ranged from 170 to 250 mm Hg, while diastolic blood pressures ranged from 100 to 150 mm Hg in affected individuals. In all affected subjects, the fundi were only minimally altered or clinically normal. All three fluorescein angiograms were normal. Despite severe hypertension since childhood the patients showed no signs of hypertensive retinopathy. CONCLUSIONS The absence of hypertensive retinopathy in this novel form of inherited hypertension is due to an altered structure of retinal arteriolar walls or some other protective mechanism. Since evidence of end organ damage is scarce in other organs as well, the protective mechanism appears to be generalised.