An (A-C)n dinucleotide repeat polymorphic marker at the 5' end of the aldose reductase gene is associated with early-onset diabetic retinopathy in NIDDM patients.

To study the relationship between the aldose reductase gene and diabetic complications, an (A-C)n dinucleotide repeat sequence 2.1 kb upstream of the transcription start site of this gene was identified and studied. There are seven alleles at this locus with a polymorphism information content of 0.73 and a heterozygosity of 0.77 among the Chinese population in Hong Kong. One of the alleles (Z-2) was found to be associated with early onset of retinopathy in patients with non-insulin-dependent diabetes (P = 0.007), suggesting that aldose reductase or a gene in the close vicinity may be involved in the pathogenesis of this diabetic complication.