MIER1 Polymorphisms and Age-Related Cataract in India

Abstract

 

Purpose:

 

Studies worldwide have reported a higher prevalence of age-related cataract in women compared to men not explained solely by access to eye care. Since the MIER1 gene may interact with estrogen receptors, we investigated associations between single nucleotide polymorphisms (SNPs) in MIER1 and cataract by gender.

 

Methods:

 

INDEYE is a population-based study of people aged 60 years and over. Participants underwent lens photography and gave a blood sample. The Lens Opacities Classification System III (LOCS III) was used for grading cataract: cortical ≥3, posterior sub capsular cataract (PSC) ≥2, nuclear cataract ≥4. Any cataract was defined as any nuclear, cortical or PSC cataract or dense opacities or operated cataract. Controls were defined as the absence of any of the above.Genotyping of MIER1 SNPs (rs912797, rs2985794, rs2755250, rs2985821, rs2985826, rs4486425) was carried out with Real Time PCR. Analysis was by logistic regression adjusted for age, sex, location and survey design.

 

Results:

 

Of 4858 participants, 433 had cortical cataract, 927 PSC, 2092 nuclear, 3531 any type of cataract and 1325 were controls. All SNPs except rs4486425 were highly correlated (r>0.9), with control MAFs of 12% and homozygous risk genotype frequencies of 2%. For rs2985821 there was a significant interaction by gender for nuclear cataract (p<0.05), similar differences were observed for other types of cataract except cortical. The correlated SNPs had similar results; rs4486425 showed no association with cataract.

 

Conclusions:

 

The homozygous risk genotypes of several MIER1 SNPs show a 3 fold association with age-related cataract in women but not in men. However the very low frequency of this genotype suggests that these MIER1 SNPs are unlikely to explain the higher prevalence of cataract in women observed in India.  

 

Keywords: gene screening • cataract • genetics