TP53 codon 72 polymorphism and the risk of glaucoma in a north Indian cohort: A genetic association study

The TP53 codon 72 Proline-Arginine polymorphism (TP53 P72R) is the most widely studied candidate among those evaluated for a putative association between impaired apoptosis and glaucoma. Considering the earlier findings about enhanced apoptotic potential by the Arg variant of TP53 P72R and the conflicting results about its association with glaucoma, we initiated a hospital-based case-control association study in a north Indian cohort to investigate the association of TP53 P72R with glaucoma.

We examined the status of TP53 P72R in 139 cases of primary open angle glaucoma (POAG) and in 111 cases of primary angle closure glaucoma (PACG) with respect to 218 controls using the polymerase chain reaction-restriction fragment length polymorphism method. Logistic regression analysis including age and gender as covariates was carried out to test the association of the polymorphism with overall glaucoma, POAG, and PACG cases.

We observed significant differences between the genotypic distributions of combined glaucoma cases and controls in the recessive model. POAG cases with respect to controls did not exhibit any significant differences in the genotypic distributions. In contrast, the genotypic distributions as per the additive and recessive models in PACG cases were significantly different from those in controls. The two models suggested an increased risk of PACG in the Arg homozygotes of the investigated cohort.

Ours is the first study demonstrating the association of TP53 P72R with the risk of PACG. It emphasizes that apart from narrow anterior chamber angle, impaired apoptotic mechanisms could also be an important contributor toward PACG.