title: EPHA2 polymorphisms and age-related cataract in India.
abstract: OBJECTIVE
  We investigated whether previously reported single nucleotide polymorphisms (SNPs) of EPHA2 in European studies are associated with cataract in India.
  
  
  METHODS
  We carried out a population-based genetic association study. We enumerated randomly sampled villages in two areas of north and south India to identify people aged 40 and over. Participants attended a clinical examination including lens photography and provided a blood sample for genotyping. Lens images were graded by the Lens Opacification Classification System (LOCS III). Cataract was defined as a LOCS III grade of nuclear ≥4, cortical ≥3, posterior sub-capsular (PSC) ≥2, or dense opacities or aphakia/pseudophakia in either eye. We genotyped SNPs rs3754334, rs7543472 and rs11260867 on genomic DNA extracted from peripheral blood leukocytes using TaqMan assays in an ABI 7900 real-time PCR. We used logistic regression with robust standard errors to examine the association between cataract and the EPHA2 SNPs, adjusting for age, sex and location.
  
  
  RESULTS
  7418 participants had data on at least one of the SNPs investigated. Genotype frequencies of controls were in Hardy-Weinberg Equilibrium (p>0.05). There was no association of rs3754334 with cataract or type of cataract. Minor allele homozygous genotypes of rs7543472 and rs11260867 compared to the major homozygote genotype were associated with cortical cataract, Odds ratio (OR) = 1.8, 95% Confidence Interval (CI) (1.1, 3.1) p = 0.03 and 2.9 (1.2, 7.1) p = 0.01 respectively, and with PSC cataract, OR = 1.5 (1.1, 2.2) p = 0.02 and 1.8 (0.9, 3.6) p = 0.07 respectively. There was no consistent association of SNPs with nuclear cataract or a combined variable of any type of cataract including operated cataract.
  
  
  CONCLUSIONS
  Our results in the Indian population agree with previous studies of the association of EPHA2 variants with cortical cataracts. We report new findings for the association with PSC which is particularly prevalent in Indians.
authors.affiliation: Department of Genetics, Dr. G. Venkataswamy Eye Research Institute, Aravind Medical Research Foundation, Aravind Eye Hospital, Madurai, Tamil Nadu, India.
authors.forename: Periasamy
authors.initials: P
authors.lastname: Sundaresan
authors.forename: Ravilla D
authors.initials: RD
authors.lastname: Ravindran
authors.forename: Praveen
authors.initials: P
authors.lastname: Vashist
authors.forename: Ashwini
authors.initials: A
authors.lastname: Shanker
authors.forename: Dorothea
authors.initials: D
authors.lastname: Nitsch
authors.forename: Badrinath
authors.initials: B
authors.lastname: Talwar
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maraini
authors.forename: Monica
authors.initials: M
authors.lastname: Camparini
authors.forename: Bareng Aletta S
authors.initials: BA
authors.lastname: Nonyane
authors.forename: Liam
authors.initials: L
authors.lastname: Smeeth
authors.forename: Usha
authors.initials: U
authors.lastname: Chakravarthy
authors.forename: James F
authors.initials: JF
authors.lastname: Hejtmancik
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002386:Cataract / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D036104:Receptor, EphA2 / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D036104:Receptor, EphA2