Testing for association between COL2A1 and myopia susceptibility in Hong Kong Chinese population

Abstract

Abstract: : Purpose: High myopia is very common in Stickler syndrome, which is caused by mutations in the α1 type II collagen gene (COL2A1). We hypothesize that some common polymorphisms within or close to this gene can be risk factors for myopia. This study tested the association between COL2A1 and myopia susceptibility in Hong Kong Chinese by family–based association study. Methods: Two hundred nuclear families were recruited, each consisting of two parents and at least one myopic child (at least –5.0DS for both eyes). Comprehensive ocular examination (refraction, axial length and corneal curvature) and venipuncture were carried out for all family members. DNA was extracted from collected blood samples for genotyping of single nucleotide polymorphisms (SNPs) in COL2A1 exons. The results were analysed with transmission/disequilibrium test (TDT) to test for association between SNP alleles and myopia. Results: Four COL2A1 SNPs (in exons 1, 7, 34 and 53) were genotyped. About 130 nuclear families have been genotyped up to now. No association between these SNPs and myopia was demonstrated by TDT analysis. Conclusions: The data suggested that there was no association between myopia and the COL2A1 gene. Genotyping of the remaining family samples are still on–going and TDT analysis with the complete family set will follow. Myopia is multifactorial and multiple genes of small effects are likely to contribute to its genesis. A large sample size is required for detecting such small genetic effects.

Keywords: myopia • genetics • gene mapping