Diabetes, lower extremity amputation, loss of protective sensation, and neuronal nitric oxide synthase associated protein in the chronic renal insufficiency cohort study.

Lower extremity amputation (LEA) is a life-altering complication of diabetes. The goal of our study was to investigate the possibility that genetic variation in neuronal nitric oxide synthase associated protein (NOS1AP) is associated with LEA and diabetic peripheral neuropathy (DPN). Our work used data from the Chronic Renal Insufficiency Cohort (CRIC) study. CRIC is a multicenter investigation undertaken to pursue the relationship between chronic renal insufficiency and cardiovascular disease. We evaluated 3,040 CRIC study subjects; 1,490 individuals were African Americans and 1,550 were whites. LEA occurred in 162 (5.3%) subjects, 93 (6.2%) of African Americans and 69 (4.4%) of whites. In whites, NOS1AP single nucleotide polymorphism rs1963645 was most strongly associated with LEA (1.73 [1.23, 2.44]). In African Americans three NOS1AP single nucleotide polymorphisms were associated with LEA: rs6659759 (1.65 [1.21, 2.24]); rs16849113 (1.58 [1.16, 2.14]); rs880296 (1.54 [1.14, 2.10]). We tested a subset of 100 CRIC participants for DPN using Semmes-Weinstein filaments. DPN in those with diabetes was associated with rs1963645 (16.97 [2.38, 120.97]) in whites and rs16849113 and rs6659759 (3.62 [1.11, 11.83] and 3.02 [0.82, 11.12], respectively) in African Americans. In conclusion, this is one of the first studies to show that NOS1AP gene variants are associated with DPN and LEA.