Familial clustering of diabetic nephropathy in Brazilian type 2 diabetic patients

There is evidence for genetic predisposition to diabetic nephropathy in typ e 1 diabetic patients. However, there are few studies on type 2 diabetic pa tients, and most of those have been conducted on ethnic minorities or Cauca sian individuals. The aim of this study was to ascertain the presence of an inherited predisposition to diabetic nephropathy in a sample of Brazilian type 2 diabetic patients. Families with two or more type 2 diabetic sibling s were identified. Subjects with the longest duration of known diabetes wer e considered probands, Some 90 probands and their 107 diabetic siblings wer e studied. Urinary albumin excretion rate was measured in a sterile 24-h ur ine sample on at least three different occasions. Probands and siblings wer e classified according to urinary albumin excretion rate as normo- (<20 mu g/min), micro- (20-200 mu g/min), or macroalbuminuric (>200 mu g/min). Pati ents with end-stage renal disease were included in the macroalbuminuric gro up. Macroalbuminuria was identified in 5.2% of the siblings of normoalbumin uric probands and in 24.1% of the siblings of macroalbuminuric probands (P = 0.024). In multiple logistic regression, the presence of diabetic nephrop athy in probands (micro- or macroalbuminuria and end-stage renal disease) w as significantly associated with the presence of sibling diabetic nephropat hy (odds ratio = 3.75, 95% CI = 1.36-10.40, P = 0.011) adjusted for proband fasting plasma glucose and diabetes duration, Interpretation of these resu lts should take into account the possibility that the families including si blings with diabetic nephropathy may have been overcounted and, on the othe r hand, that the siblings without diabetic nephropathy may have been underc ounted, In conclusion, there is a familial aggregation of diabetic nephropa thy in this sample of type 2 diabetic patients.