Association Of Insulin-like Growth Factor-1Polymorphisms With Extreme High Myopia In Chinese Population

Purpose: To investigate the association between genetic variants in the insulin-likegrowth factor-1(IGF-1) gene and its regulatory regions with extreme high myopia in Chinesepopulation.Methods: A case-control association study of302unrelated patients with extreme highmyopia who have a spherical equivalent (SE) refractive error less than-10.0D and an axiallength greater than26mm in both eyes and401control subjects matched in ethnicity andgender who have spherical refractive error ranging from-0.50to+2.00D and an axial lengthless than24mm in both eyes were undertaken. The comprehensive ophthalmic examinationand peripheral blood collection were performed for all of the subjects.7tag single nucleotidepolymorphisms (tSNPs) were selected to capture the majority of genetic variation, knownSNPs encompassing the coding region of IGF-1, as well as the regions9.8kb upstream of thestart codon and8kb downstream of the stop codon based on the HapMap CHB (Han Chinesein Beijing, China) population. All tSNPs were genotyped using the MassArray platform andMALDI-TOF analysis. Genotypic distribution was tested for Hardy-Weinberg equilibrium.Statistical analyses were performed on computer using the SPSS (version13.0: SPSS Science,Chicago, IL) software. The genotype and allele frequencies were evaluated using the2tests.Bonferroni corrections for multiple comparisons were performed. The significance of thedifferences in the estimated haplotype frequencies between case and control groups wereexamined on Haploview4.2using the2tests, and haplotypes were corrected by usingpermutation test after running50,000times. Results: Among7IGF-1tSNPs tested, four tSNPs—rs5742629, rs12423791, rs35766and rs1457601showed significant differences (p<0.05) in comparison of allele frequencies.The polymorphism of rs12423791showed positive association with extreme high myopiaafter Bonferroni correction. The haplotype GC of rs5742629-rs12423791was also associatedwith extreme high myopia (p=0.033) after50,000permutations for multiple comparisons.Conclusions: The polymorphism of rs12423791in the IGF-1gene may be associatedwith extreme high myopia in Chinese population and should be investigated further.