Renal tubular dysgenesis: evidence of abnormality in the renin-angiotensin system.

Renal tubular dysgenesis is an autosomal recessive condition characterized by short, abnormally developed cortical tubules that lack proximal differentiation. Despite the lack of normal proximal tubules, the major site of water resorption in the kidney, the principal clinical manifestations are caused by fetal and neonatal oliguria. The kidneys in three cases of neonatal renal tubular dysgenesis were found to contain large amounts of immunohistochemically reactive renin in preglomerular arterioles, glomerular hilums, and glomerular mesangial areas, far exceeding the intensity of staining and the numbers of sites stained in control kidneys. The increased accumulation of renin may reflect strong local vasoconstriction, which is responsible for reduced glomerular perfusion. This accumulation suggests faulty feedback control of renin secretion, the basis of which is still to be identified.