title: Polymorphisms of the gamma crystallin A and B genes among Indian patients with pediatric cataract.
abstract: BACKGROUND
  Previous familial studies have reported co-segregation of mutation in gamma crystallin A and B CRYGA and CRYGB genes with childhood cataract.
  
  
  OBJECTIVE
  We investigated association of nucleotide variations in these genes in subjects with and without pediatric cataract from India.
  
  
  METHODS
  The study included 195 pediatric subjects including healthy children with no ocular defects and pediatric cataract cases.
  
  
  METHODS
  Subjects were genotyped by PCR-RFLP method for exonic and intronic genetic variations in CRYGA and CRYGB.
  
  
  METHODS
  The association of these polymorphisms with cataract was estimated by two way contingency tables and the risk allele was also analyzed for their functional impact using in silico tools. Results : No significant difference was observed between cases and control subjects for the frequencies of SNPs G198A (Intron A), T196C (Exon 3) of CRYGA and G449T (Exon 2) of CRYGB gene. -47C allele of rs2289917 in CRYGB showed the strongest association with cataract (Odd Ratio-OR=3.34, 95% Confidence Interval-CI 95% =1.82-6.12, P=0.00007). In silico analyses revealed that this polymorphism lies in a phylogenetically conserved region and impacts binding of a transcription factor, viz. progesterone receptor (PR) to CRYGB promoter.
  
  
  CONCLUSIONS
  rs2289917 risk allele showed a strong association with increased vulnerability for pediatric cataract. The findings suggest that this association may be a secondary phenomenon related to genetic variation playing critical role in lens development during perinatal and/or pediatric growth. Present exploratory study provides a basis for further defining the role of PR as a regulator of CRYG locus in lens formation/transparency.
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science- Pilani, Hyderabad Campus, Hyderabad, Andhra Pradesh, India.
authors.forename: S
authors.initials: S
authors.lastname: Mehra
authors.forename: S
authors.initials: S
authors.lastname: Kapur
authors.forename: A R
authors.initials: AR
authors.lastname: Vasavada
mesh_terms: D002386:Cataract / Q000453:epidemiology / Q000235:genetics* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000235:genetics*; D005091:Exons; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007438:Introns; D008297:Male; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012189:Retrospective Studies; D038222:gamma-Crystallins / Q000235:genetics* / Q000378:metabolism
chemical_list: C107738:crystallin, gammaB; D038222:gamma-Crystallins; D004247:DNA