Sclera-related gene polymorphisms in high myopia

PURPOSE: Transforming growth factor-β2 (TGF-β2), basic fibroblast growth factor (bFGF), and fibromodulin (FMOD) are important extracellular matrix components of the sclera and have been shown to be associated with the development of high myopia. Our aim was to examine the association between myopia and the polymorphisms within TGF-β2, bFGF, and FMOD. METHODS: The study group comprised of patients (n=195; age range: 17−24 years) with a spherical equivalent of −6.5 diopters (D) or a more negative refractive error. The control group comprised of individuals (n=94; age range: 17−25 years) with a spherical equivalent ranging from −0.5 D to +1.0 D. The subjects with astigmatism over –0.75 D were excluded from the study. High resolution melting (HRM) genotyping and restriction fragment length polymorphism (RFLP) genotyping were used to detect single nucleotide polymorphisms (SNPs). The polymorphisms detected were TGF-β2 (rs7550232 and rs991967), bFGF (rs308395 and rs41348645), and FMOD (rs7543418). Moreover, a stepwise logistic regression procedure was used to detect which of the significant SNPs contributed to the main effects of myopia development. RESULTS: There were significant differences in the frequency of the A allele and A/A genotype in TGF-β2 (rs7550232; p=0.0178 and 0.03, respectively). Moreover, the haplotype distribution of haplotype 2 (Ht2; A/A) of TGF-β2 differed significantly between the two groups (p=0.014). The results of the stepwise logistic regression procedure revealed that TGF-β2 (rs7550232) contributed significantly to the development of high myopia. CONCLUSIONS: TGF-β2 is an important structure of sclera and might contribute to the formation of myopia. TGF-β2 (rs7550232) polymorphisms, A allele and A/A genotype, had a protective role against the development of high myopia.