Evaluation of thrombospondin�gene polymorphisms in corneal allograft rejection in Asian Indian patients

ABSTRACT

Purpose: To evaluate the frequency and the association of Thrombospondin 1 (THBS1) gene single nucleotide polymorphisms (SNPs) in Asian Indian patients with optical full thickness corneal grafting surgery. Methods: Prospective case朿ontrol analysis of optical penetrating keratoplasty patients with and without immune rejection and controls for genotyping of 3 THBS1 gene SNPs (rs1478604 A>G; rs2228261 C>T; rs2228262 A>G) by Amplification Refractory Mutation System-Polymerase Chain Reaction (ARMS PCR). Results: Among 58 patients [45 with immune allograft rejection (DNA isolation was possible in 38 samples) and 13 without immune corneal allograft rejection] and 65 controls, allele frequencies observed for rs1478604 (A>G) are A 69.7% and 72.6%, G 30.2% and 27.3%; for rs2228261 (C>T) are T 70.2% and 62.3%, C 29.7% and 37.6%; and for rs2228262 (A>G) A 97.4% and 98.4%; G 2.5% and 1.5% respectively. Genotype frequencies were rs1478604 (A>G) AA 57.8% and 59.3%, AG 23.6% and 26.5%; GG 18.4% and 14%; for rs2228261 (C>T) TT 40.5% and 33.8%, TC 59% and 56.9%, CC 0% and 9.2%; for rs2228262 (A>G) AA 94.8% and 96.8%, AG 5.1% and 3.1% in rejection and controls respectively. The allele and genotype frequency for the 3 described THSB1 SNPs did not show any difference between the corneal graft immune rejection patients and controls. Conclusion: Asian Indian population evaluated for THBS1 gene SNPs by ARMS PCR genotyping in Asian Indian population did not show any genetic association to immune rejection occurrence in our study.