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.

AIM:

We investigated association of nucleotide variations in these genes in subjects with and without pediatric cataract from India.

SETTINGS AND DESIGN:

The study included 195 pediatric subjects including healthy children with no ocular defects and pediatric cataract cases.

MATERIALS AND METHODS:

Subjects were genotyped by PCR-RFLP method for exonic and intronic genetic variations in CRYGA and CRYGB.

STATISTICAL ANALYSIS:

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.

CONCLUSION:

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: S Mehra, S Kapur, A R Vasavada
• Journal: Journal of postgraduate medicine (J Postgrad Med) 2011 Jul-Sep Vol. 57 Issue 3 Pg. 201-5 ISSN: 0972-2823 [Electronic] India
• PMID: 21941057 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• crystallin, gammaB
• gamma-Crystallins
• DNA

Topics

• Cataract (epidemiology, genetics, metabolism)
• Child
• Child, Preschool
• DNA (genetics)
• Exons
• Female
• Gene Frequency
• Genetic Predisposition to Disease
• Genotype
• Humans
• Incidence
• India (epidemiology)
• Introns
• Male
• Pilot Projects
• Polymerase Chain Reaction
• Polymorphism, Genetic
• Retrospective Studies
• gamma-Crystallins (genetics, metabolism)