Influence of the genetic polymorphism of haptoglobin in the occurrence of retinopathy and nephropathy in diabetics subjects

The objective of this study was to determine the frequency of haptoglobin (Hp) genotypes and their association with nephropathy and retinopathy in diabetic subjects. This is a case-control study conducted in diabetic subjects developing nephropathy and/or retinopathy. Each patient was matched to a control of the same sex and the same age ± 2 years. Hp genotyping was performed by conventional PCR without enzymatic digestion on the Proflex® System PCR (Biosystems, Spain) and the biochemical parameters were determined using enzymatic techniques with the Cobas c311 system (Roche Diagnostics, Switzerland). The study population consisted of 60 diabetic subjects with an average age of 56 years and a sex ratio of 0.43. The Hp2-2 genotype was more frequent in diabetic subjects (40%) compared to control subjects (28.3%) (p= 0.18). The distribution of Hp1-1 and Hp2-1 genotypes in diabetic subjects showed rates of 46.7 and 13.3% respectively. Multivariate analysis showed that the Hp 2-2 genotype was more associated with nephropathy (OR=1.77; p=0.8). These results showed an association between Hp polymorphism and diabetic microangiopathy. Thus, Hp2-2 genotype could be associated with a risk factor predisposing to the onset of diabetic kidney disease.   Key words: Polymorphism, gene, haptoglobin, diabetes, nephropathy, retinopathy.