GENETIC PREDISPOSITION TO HYPERTENSION (AS DETECTED BY NA+ LI+ COUNTERTRANSPORT) AND RISK OF DIABETIC NEPHROPATHY IN CHILDHOOD DIABETES/

In order to evaluate whether insulin-dependent diabetes mellitus patie nts with incipient nephropathy have an overactivity of erythrocyte sod ium-lithium countertransport (Na+/Li+ CT), 82 diabetic children and 38 healthy age-matched control subjects and their parents and grandparen ts were studied. The children were divided into two groups according t o the presence of persistent microalbuminuria (MA). Diabetic children with MA had Na+/Li+ CT activity higher than normoalbuminuric diabetics and healthy controls. The parents and grandparents of microalbuminuri c patients showed higher Na+/Li+ CT than parents and grandparents of n ormoalbuminuric diabetics and of the controls. This study demonstrates that predisposition to hypertension, as indicated by increased Na+/Li + CT activity in erythrocytes, is more frequently detectable in patien ts with persistent microalbuminuria than in diabetics without persiste nt microalbuminuria or in healthy controls. Overactivity of Na+/Li+ CT is present also in parents and grandparents of diabetic children with MA. This study suggests that genetic predisposition to hypertension i s more frequent in patients at risk of developing diabetic nephropathy , as well as in their parents and grandparents.