Purpose Genome-wide association study (GWAS) of high myopia in Chinese population found several single nucleotide polymorphisms (SNPs) associated with myopia. This study is to examine if these SNPs are associated with high myopia in the Chinese subjects we collected as the original study suggested replication studies to validate their findings.
Methods  There are totally 600 unrelated individuals participated in this study, including high myopia patients (spherical refraction at each meridian at least ≤-6.00D) and subjects without myopia (bilateral spherical equivalent refraction between -0.50D and +2.00D). Genomic DNA was isolated from venous blood using standard phenol/chloroform method. Three SNPs, which were associated with myopia in original study, were genotyped. These SNPs  were genotyped by snapshot and direct sequencing. The genotype and allele frequencies of the SNPs between myopias and controls were compared by chi-squared test. The statistical analysis was performed by SPSS 16.0 (SPSS Science, Chicago, IL).
Results Totally 600 subjects were involved in this study, including 300 subjects with complex high myopia and 300 normal controls. There was statistically significant difference for allele frequencies of the three SNPs between myopias and controls in the Chinese individuals we analyzed (P=0.04).
Conclusions This study support the association of complex high myopia with three SNPs in 4q25, which were found in the original study.