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

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.

This case-control study compared a study group (n=188) with high myopia whose spherical equivalent was greater than -6.0 D with a control group (n=85) whose spherical equivalent was less than -0.5 D. Genotyping of IVS9-12C to T was conducted by restriction fragment length polymorphism analysis, and results were compared for the two groups.

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 -10 D) 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).

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.