To investigate whether the polymorphisms of insulin-like growth factor-1 (IGF-1) gene and its regulatory regions are associated with extreme high myopia.

A casecontrol analysis of 302 subjects with extreme high myopia and 401 controls was undertaken.Genomic DNA was obtained from peripheral blood.Seven tag single nucleotide polymorphisms (tSNP) across the IGF-1 gene region were selected to capture the majority of genetic variation.All tSNP were genotyped using the Mass Array platform and MALDI-TOF analysis.Genotypic distribution was tested for Hardy-Weinberg equilibrium.Statistical analyses were performed using the SPSS (version 13.0:SPSSScience,Chicago,IL) software.The genotype and allele frequencies were evaluated using theχ²tests and performed by Bonferroni corrections for multiple comparisons.The significance of the differences in the estimated haplotype frequencies between the myopia and control groups was examined on Haploview 4.2 usingχ²tests,and haplotypes were corrected by using permutation test after running 50 000 times.

Among seven different IGF-1 tSNP tested,the allele frequencies of four tSNP-rs5742629 (A/G),rs12423791 (G/C),rs35766 (G/A) and rs1457601 (T/A) in the myopia and the control groups were A (56.5%,62.3%) /G (43.5%,27.7%),G (70.4%,77.1%) /C (29.6%,22.9%),G (33.9%,28.8%) /A (66.1%,71.2%),T (72.5%,77.3%) /A (27.5%,22.7%),respectively.And they showed significant differences (χ²=4.968,8.059,4.250,4.245,P<0.05) between the two groups.However,only rs12423791 remained significance after Bonferroni correction.The haplotype GC of rs5742629-rs12423791 was associated with extreme high myopia (P=0.033) after 50 000 permutations for multiple comparisons as well.

The polymorphism of rs12423791 in IGF-1 may be associated with extreme high myopia in the Chinese population. (ChinJ Ophthalmol,2013,49:334-339)

Myopia; Insulin-like growth factorⅠ; Polymorphism,single nucleotide