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Length rather than a specific allele of dinucleotide repeat in the 5′ upstream region of the aldose reductase gene is associated with diabetic retinopathy


Dr Hiroshi Ikegami, Department of Geriatric Medicine, Osaka University Medical School, 2–2 Yamadaoka, Suita, Osaka 565, Japan. E-mail:


Aims To assess the possible contribution of a genetic factor to diabetic retinopathy.

Methods (CA)n repeat length was investigated in the 5′ upstream region of the gene coding for aldose reductase (AR), which is a key enzyme of the polyol pathway and plays a role in hyperglycaemia-induced tissue damage, in Japanese patients with Type 2 DM.

Results The dinucleotide repeat length was significantly associated with proliferative diabetic retinopathy (PDR) (P=  0.029, Mann–Whitney U-test); i.e. shorter alleles were more prevalent in the PDR group than in the control group.

Conclusions (CA)n repeat length, rather than a specific allele, in the 5′ upstream region of the AR gene is associated with diabetic retinopathy. These data suggest that the AR locus plays a role in genetic susceptibility to diabetic retinopathy and that dinucleotide repeats in genomic DNA may be related to disease predisposition.