RESUMO
Polymorphisms of the -106 mutation and z - 2 or z + 2 microsatellites (-2.1 kb) of the Aldose Reductase (AR) gene have been associated to microangiopathic complications of the diabetes mellitus. The study aimed to establish a relation between the occurrence and progression of the renal and retinal complications and these polymorphisms. The genotypes were realised in 3 populations: DESIR (n = 369), non-diabetic control subjects from the general French population: GENEDIAB (n = 494), type 1 diabetic patients who are suffering from proliferative retinopathy associated with a variable seriousness nephropathy (absent: n = 157; incipient: n = 104; established: n = 126; advanced: n = 107); SURGENE (n = 310), type 1 diabetic patients whom the renal status is prospectively assessed since 1989 in one single center Angers University Hospital. The genotype of the -106 polymorphism was determined using the Molecular Beacons. For the microsatellites analysis, we used an automatized method (GeneScan Abi Prism 3100). There was a strong linkage disequilibrium between the z - 2 allele and the T allele (chi 2 = 120; p = 0.001). The frequency of the C-106T is similar for the DESIR and GENEDIAB cohorts (chi 2 = 3.32; p = 0.19); the Hardy Weinberg law was verified in this group (chi 2 = 0.001, 0.9; p = 1.5 and 0.5 respectively). The law was not verified for the SURGENE cohort (chi 2 = 4.7; p = 0.03) where the frequency of the TT genotype was significantly more important compared to the DESIR population (chi 2 = 6.4; p = 0.01). The z, z - 2 and z + 2 alleles was more frequent compared with other alleles (n = 909, 830 and 349; 39, 38 and 15%). The frequency of the C-106T and microsatellites genotypes did not parallel the nephropathy staging in the GENEDIAB population (chi 2 = 10.9, 2.7, 2.4; p = NS respectively). In the SURGENE population, the survival without renal events did not differ according C-106T and z - 2 or z + 2 microsatellites genotypes (log-rank: 0.6, 3.9, 0.1; p = NS respectively). At the end of the follow-up, we found an effect of the -106 mutation and of the z - 2 microsatellite on the staging of the retinopathy (chi 2 tendency test = 4.61, 0.12; p = 0.031, 0.02; 6 d.f., respectively). The logistic regression multivariable analysis shows that the retinopathy during the final evaluation is independently explained by several factors: diabetes duration (p < 0.0001; OR 21.756; 95% CI: 7.024-67.389), presence of nephropathy (p < 0.0001; OR: 4.086; 95% CI: 2.094-7.973), and genotype TT (p = 0.011; OR: 0.38; 95% CI: 0.18-0.803). In contrast, age of diabetes onset (p = 0.112; OR: 1.556; 95% CI: 0.9-2.692), median HbA1c (p = 0.164; OR: 1.479; 95% CI: 0.85-2.576) and sex (p = 0.156; OR: 1.495; 95% CI: 0.856-2.612) have no independent effect. In conclusion, the association of these AR genetic variants seems absent about the renal risk and slight about the retinal risk associated to the type 1 diabetes mellitus.
