P. Olmos et al., (AC)(23) [Z-2] polymorphism of the aldose reductase gene and fast progression of retinopathy in Chilean type 2 diabetics, DIABET RE C, 47(3), 2000, pp. 169-176
A recent case-control study suggests that the allele (AC)(23) of a variable
number tandem repeat (VNTR) associated to the aldose reductase (ALR2) gene
could be related to early retinopathy in Type 2 diabetics. By means of a l
ongitudinal-retrospective study, we aimed to seek for a relationship betwee
n the rate of progression of retinopathy and the (AC)(23) allele of the VNT
R associated to the ALR2 gene. A random sample was obtained of 27 Type 2 di
abetics (aged 68.1 +/- 10.6 years, diabetes duration = 20.7 +/- 4.8 years,
mean HbA1 = 10.6 +/- 1.6%). The mean HbA1 was the arithmetic average of 2.2
measurements per patient per year of total glycosilated hemoglobin (Gabbay
method, normal range: 4.2-7.5%). Retinopathy was graded by an Ophthalmolog
ist in a scale from zero to four score points. The genotype of the (AC)(n)
VNTR was determined by 32P-PCR plus sequenciation in a Perkin-Elmer laser d
evice. The Mann-Whitney test and either chi(2) or Fisher's exact test were
used. A P < 0.05 was considered as statistically significant. The retinopat
hy progression rate (RPR, points x year(-1)) was calculated by dividing the
increment of retinopathy score (Delta Retinopathy Score, [points]), by the
duration of the follow up [years]. The 12 diabetics having the (AC)(23) al
lele had a mean RPR 8.9 times higher (0.40 +/- 0.61 points x year(-1)) than
the 15 patients who had alleles other than (AC)(23) (0.045 +/- 0.099 point
s x year(-1), P = 0.037). Both groups were similar with respect to: mean Hb
A1 (10.5 +/- 1.4 and 10.7 +/- 1.7%, P = 0.95), age at diagnosis (48.5 + 6.3
and 46.3 + 14.0 years, P = 0.81), diabetes' duration (21.3 +/- 4.7 and 20.
2 +/- 4.9 years, P = 0.41) and serum creatinine (0.89 +/- 0.2 and 1.13 +/-
0.5 mg dl(-1), P = 0.35). We concluded that, in Type-2 diabetics having sim
ilar glycemic control, the (AC)(23) allele of the VNTR associated to the AL
R2 gene, is associated to a 8.9 times faster progression of retinopathy tha
n in patients who have other alleles. (C) 2000 Elsevier Science Ireland Ltd
. All rights reserved.