Albumin excretion rate levels in non-diabetic offspring of NIDDM patients with and without nephropathy

Familial clustering of diabetic nephropathy points to genetic susceptibility. The observation that in non-diabetic subjects microalbuminuria occurs more frequently in the presence of a parental history of diabetes supports this hypothesis. However, the role of inherited factors is poorly understood in non-insulin dependent diabetes mellitus (NIDDM). This study investigated the albumin excretion rate in non-diabetic offspring of NIDDM patients with increased albumin excretion rate (>20 Μg/min) or normal albumin excretion rate (<20 Μg/min). We recruited 20 offspring of NIDDM patients with increased albumin excretion rate (A-off) and 20 offspring of NIDDM patients with normal albumin excretion rate (N-off), matched for age, sex, body mass index, blood pressure and estimated protein intake. All offspring were normotensive, had normal creatinine clearance, normal glucose tolerance and sterile urine collection. Albumin excretion rate was measured on three sterile overnight urine collections and median values were used for calculations. Albumin excretion rate was significantly higher in A-off than in N-off (7.7±1.2 vs 3.4±0.6 Μg/min p<0.01) and significantly related to parents' albumin excretion rate (p<0.01, r=0.53). These results suggest that an increased glomerular permeability is present in non-diabetic offspring of NIDDM patients with increased albumin excretion rate.