Purpose: Myopia is the most common human eye disorder with complex genetic and environmental causes. To date, several myopia loci have been identified in families of different geographic origin. However, no causative gene(s) have yet been identified. The aim of this study was the characterization of Polish families with high-grade myopia, including genetic analysis.
Methods: Forty-two multiplex Polish families with non-syndromic high-grade myopia participated in the study. All family members underwent detailed ophthalmic examination and high-grade myopia was defined as ≤-6.0 diopters (D) based on the spherical refractive error. A genome-wide single nucleotide polymorphism (SNP)-based high-density linkage scan was performed using Affymetrix Human SNP Array 6.0 on a selected family (HM-32) with multiple affected individuals.
Results: Nonparametric linkage analysis identified three novel loci in family HM-32 at chromosome 7p22.1-7p21.1 ([NPL] 8.26; p=0.006), chromosome 7p12.3-7p11.2 ([NPL] 8.23; p=0.006), and chromosome 12p12.3-12p12.1 ([NPL] 8.02; p=0.006), respectively. The effect of linkage disequilibrium on linkage due to dense SNP map was addressed by systematically pruning SNPs from the linkage panel.
Conclusions: Haplotype analysis with informative crossovers in affected individuals defined a 12.2; 10.9; and 9.5 Mb genomic regions for high-grade myopia spanned between SNP markers rs11977885/rs10950639, rs11770622/rs9719399, and rs4763417/rs10842388 on chromosomes 7p22.1-7p21.1, 7p12.3-7p11.2, and 12p12.3-12p12.1, respectively.