Association of PON2 and PON3 polymorphism with risk of developing cataract

Paraoxonases (PON) are calcium bound enzymes offering protection against oxidative stress by working as endogenous free-radical scavenging molecules. Oxidative stress has been implicated in pathophysiology of many diseases including cataract. Lens opacity is an age related disorder which is a principal cause of blindness in Pakistani population. Relationship of PON2 and PON3 polymorphism with genetic predisposition for incidence of cataract has not been investigated till date. Objective of the current study was to explore possible association between PON2 and PON3 polymorphism with incidence of cataract in local population.

Our study design comprised of fifty-one cataractous and fifty-nine healthy individuals. Identification of single nucleotide polymorphism (SNP) at positions (C311S and G148A) for PON2 and C133A for PON3 was conducted using restriction fragment length polymorphism (RFLP).

Statistical analysis revealed significant association of PON2 G148 allele with incidence of cataract. GG allele was found to be higher in cataract patients as compared to control (p < 0.001) suggesting distribution of PON2 G148A genotype and allele frequency is linked with cataractogenesis. There was no noticeable association between PON2 C311S and PON3 C133A. Significant difference was observed in distribution of 311CS/148A combined genotype with highest frequency in control individuals (88.89%), while 311S/148G combined genotypes showed the highest frequencies among the cataract patients (71.42%).

Our data suggests mutation at G148A might be related with incidence of cataract in studied population.