Association of three single nucleotide polymorphisms at the SIX1-SIX6 locus with primary open angle glaucoma in the Chinese population.

Jinghong Sang,Liyun Jia,Ningli Wang,Nihong Zhang,Huaizhou Wang,Bowen Zhao

doi:10.1007/s11427-016-5073-y

Abstract

This study investigated the genetic association of three single nucleotide polymorphisms (SNPs; rs10483727, rs33912345, and rs146737847) at the SIX1-SIX6 locus with primary open angle glaucoma (POAG) in the Chinese population. A total of 866 subjects with POAG (685 high-tension glaucoma (HTG) and 181 normal-tension glaucoma (NTG)) and 266 control individuals were included. Significant genetic association was identified for rs10483727 in HTG (P=0.02; odds ratio (OR)=1.31), NTG (P=7.41×10(-6); OR=2.71), and POAG (i.e., HTG and NTG combined; P=0.001; OR=1.44). rs33912345 was also significantly associated with HTG (P=0.008; OR=1.36), NTG(P=2.72×10(-6); OR=2.27), and POAG (P=3.84×10(-4); OR=1.49). The rare SIX6 mutation, rs146737847, was not found in the subjects enrolled in this study. Stratification by patient age identified that both rs10483727 and rs33912345 were significantly associated with NTG in patients aged above 40 years (P=2.08×10(-5); OR=2.28), whereas in patients aged between 20-40 years, rs33912345 was significantly associated with NTG (P=0.017; OR=2.06). In HTG, the genetic associations for both rs10483727 and rs33912345 were significant in patients aged between 20-40 years (P=0.006; OR=1.56) but not in those aged above 40 years (P=0.118, OR=1.21 and P=0.042, OR=1.29, respectively). This study replicated the association of POAG with two SNPs at the SIX1-SIX6 locus and demonstrated that SNPs, rs10483727 and rs33912345, are significantly associated with POAG, especially with NTG in patients aged above 40 years.

Highlights

Glaucoma is the leading cause of irreversible blindness worldwide (Quigley and Broman, 2006)
This study investigated the genetic association of three single nucleotide polymorphisms (SNPs; rs10483727, rs33912345, and rs146737847) at the SIX1-SIX6 locus with primary open angle glaucoma (POAG) in the Chinese population
In the Handan Eye study, normal-tension glaucoma (NTG) accounted for 90% of patients with primary open angle glaucoma (POAG); the proportion might be even higher in the Japanese population, in which 92% of the patients

Summary

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness worldwide (Quigley and Broman, 2006) It is characterized by typical optic nerve atrophy owing to the death of retinal ganglion cells and visual field loss. POAG is a genetically complex disorder with a wide spectrum of phenotypes Ocular quantitative traits such as central corneal thickness and optic nerve parameters contribute to increased risk of POAG and its progression (Wiggs et al, 2012). A recent clinical and functional study of the SIX6 gene identified a common variant (rs33912345) to be significantly associated with POAG and it was further found that patients homozygous for the rs33012345 “T” risk allele were predisposed to have a thinner retinal nerve fiber layer than patients homozygous for the non-risk allele “C” (Carnes et al, 2014).

RESULTS

DISCUSSION

MATERIALS AND METHODS