Cells damaged by hyperglycemia are unable to downregulate glucose entrance in presence of high extracellular glucose resulting in intracellular activation of deleterious biochemical pathways. Expression of GLUT-1, the major glucose transporter in mesangial cells, is increased and participates in the induction of diabetic nephropathy. Variants in the gene encoding GLUT-1 (SLC2A1) have been associated to this diabetic complication. The aim of this study was to test whether polymorphisms in SLC2A1 confer susceptibility to diabetic nephropathy in Brazilian type 1 diabetes patients.

In this study, 449 patients, included between October 2004 and October 2012, were sorted into three groups according to diabetic nephropathy stages: without (persistent normoalbuminuria, n=248), incipient (microalbuminuria, n=82) and overt diabetic nephropathy (macroalbuminuria or proteinuria or renal replacement therapy, n=119). Measurements of urinary albumin-to-creatinine ratio (ACR) or urinary albumin excretion rate (UAER) were used to define DN: patients with persistent normoalbuminuria (<30 mg/g creatinine or <20 μg/min) were classified as without DN (n=248); patients presenting persistent microalbuminuria (30-300 mg/g creatinine or 20-200 μg/min) were classified as having incipient DN (n=82); and patients presenting persistent macroalbuminuria (>300 mg/g creatinine or >200 µg/min), proteinuria (>500 mg/24 h) or renal replacement therapy were classified as having overt DN (n=119). Genotyping of polymorphisms was performed by Real Time PCR using fluorescent -labelled probes.

Inclusion Criteria:

• Overt 10 years of Diabetes Mellitus

Exclusion Criteria:

• Patients presenting autoimmune diseases, HIV or HCV infections
• Patients with glomerular filtration rate < 60 mL min-1 1.73 m2 without diabetic retinopathy

449 patients with type 1 diabetes (56.4% female, mean age 36.0±11.0 years) were included between October 2004 and October 2012. Inclusion criterion was type 1 diabetes duration ≥10 years. The patients presented a mixed ethnic background (European Caucasian, African, Amerindian and Asian of several different countries of origin), which reflects the Brazilian population.