Purpose  Age-related cataract (ARC) is a complex multi-factorial disorder involving a number of genetic and environmental factors. Major intrinsic protein of lens fiber (MIP) encodes the most abundant junctional membrane protein in the mature lens and plays a critical role in maintainace of lens internal circulation and normal structure. To determine the relationship between SNPs in MIP and the susceptibility to ARC in a Chinese population, we conducted this case-control study.
Methods  A total of 164 unrelated ARC patients and 132 normal controls were involved in the study. All participants completed full physical and ophthalmic examinations and provided a blood sample for DNA extraction. Five SNPs (rs2269348, rs61759527, c.-4T>C, rs77163805 and rs74641138) in MIP were amplification by polymerase chain reaction (PCR) and sequenced. The genotype and allele frequencies of these SNPsfrom patients and controls were compared using SNPstats.
Results  Polymorphism rs61759527 and rs77163805 was not detected in all 296subjects. There are statistical differences in genotype and allele frequencies of c.-4C>T between ARC cases and controls. Cataract patients had a higher TC/CC genotype (OR=6.18，P=0.0018) and C allele frequency (OR=3.293，P=0.017). The haplotype CCG of rs2269348、c.-4T>C and rs74641138 exhibited a signi?cantly higher distribution in cases than controls (OR=8.83，P=0.0024).
Conclusions  Our findings indicate that the polymorphisms c.-4T>C and haplotype CCG of rs2269348、c.-4T>C and rs74641138 in MIP may attach an additional genetic risk factor for ARC in Chinese. This is the first association study about the SNPs in MIP and susceptibility to ARC in Chinese population.