A PAX6 gene polymorphism is associated with genetic predisposition to extreme myopia

Abstract

Purpose: The PAX6 gene is a homeobox gene involved in oculogenesis, ocular growth, and form-deprivation myopia. Our aim was to determine whether PAX6polymorphism at position -12 of intron 9 (IVS9-12C to T, rs667773) is associated with high myopia in Chinese Taiwanese. Methods: This case-control study compared a study group (n = 188) with high myopia whose spherical equivalent was greater than -6.0D with a control group (n = 85) whose spherical equivalent was less than -0.5D. Genotyping of IVS9-12C to T was conducted by restriction fragment length polymorphism analysis, and results were compared for the two groups. Results: No significant difference in genotype and allelic frequency at this position between the study and control groups was detected. However, there was a significantly higher frequency of the CC genotype in extremely myopic (greater than -10D) patients (P < 0.001, odds ratio (OR = 5.265), confidence interval (CI = 2.0342-13.626)). Furthermore, there was a higher frequency of the C allele in the extreme myopia group than in the control group (P = 0.002, OR = 3.73, CI = 1.57-8.81). Conclusions: The elevated frequency of the CC genotype within the extreme myopia group indicated that the CC genotype could act as a genetic marker, identifying patients predisposed to develop extreme myopia. Varied expression of this genotype may contribute to the genetic predisposition to high myopia in Chinese Taiwanese.