Purpose: To investigate the relation between myopia and variations in three genes coding for matrix metalloproteinases, enzymes that degrade matrix proteins and modulate scleral extensibility.
Methods: Three hundred sixty-six men and women, from Sheffield, United Kingdom, were genotyped for the 1G/2G polymorphism in the MMP-1 gene, the 5A/6A polymorphism in the MMP-3 gene and the Arg-->Gln polymorphism in exon 6 of the MMP-9 gene and assessed for refractive error.
Results: Risk of myopia was increased in people homozygous for the 5A allele of the MMP-3 gene (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.1-9.0) compared to those who were homozygous for the 6A allele, and in people homozygous for the Gln allele in exon 6 of the MMP-9 gene (OR, 2.8; 95% CI, 1.1-7.0) compared to those who were homozygous for the Arg allele. People who were homozygous for the 2G allele of the MMP-1 gene had an odds ratio for myopia of 2.3 (95% CI, 0.9-6.1), compared with those who were homozygous for the 1G allele, although this relation did not reach statistical significance. Risk of myopia increased progressively with the dose of these three alleles, showing a greater than 10-fold difference across the range.
Conclusions: The results suggest that common variations in three of the genes that control breakdown of matrix proteins in the sclera may contribute to the development of simple myopia.