Abstract [Download PDF] [Read Full Text]
Background
Age-related macular degeneration (AMD) is the main cause of irreversible loss of central vision in old population.The incidence of AMD is increasing year by year,but the mechanism is not clearly understood.
Objective
This study was to investigate the association between genetic variants and the risk of AMD in Ningxia population.
Methods
This study was approved by Ethic Committee of Ningxia People’s Hospital and complied with the Helsinki Declaration.Written informed consent was obtained from each subject.One hundred and fifty patients with AMD and 145 ethnicity- and gender-matched controls were recruited in Ningxia Eye Hospital from January 2012 to March 2013.All individuals underwent comprehensive eye examinations and genomic DNA was prepared from peripheral blood.The single nucleotide polymorphisms (SNPs) of 8 susceptibility loci in four candidate genes,including complement factor H (CFH),complement factor B (CFB),age-related maculopathy susceptibility 2 (ARMS2) and high temperature required factor A1 (HTRA1),were genotyped with Mass Array and MALDI-TOF technique by Sequenom platform.The distribution of genotype was tested for Hardy-Weinberge equilibrium (HWE).The differences of genotype distribution of allele and haplotype frequencies were compared between patients and controls using chi-squared test and the P value was significant at <0.006 level after correction of age,and the relationship of genotype distribution with AMD was evaluated by Logistic regression analysis.Measures of linkage disequilibrium (LD) was carried out by Haploview.
Results
All the genetypes met HWE.Seven SNPs were found to be different in the genotypic distributions and allele frequencies between patients and normal controls (all at P<0.05),however,after Bonferroni correction,the differences of only four SNPs were significant between the patients and controls in the genotype and allele distributions,including the SNPs of rs10737680 and rs1410996 in CFH gene,the SNP of rs10490924 in ARMS2 gene and SNP of rs11200638 in HTRA1 gene. The allele distributions of rs800292 (Pallele=0.006,OR=1.643,95%CI:1.155-2.336) in CFH and rs641153 (Pallele=0.002,OR=0.273,95%CI:0.120-0.620) in CFB were significantly associated with AMD.In addition,five SNPs in CFH gene were consisted of two blocks after analysis by Haploview.In addition,five SNPs in CFH were consisted of two blocks after analysis by Haploview.The first one SNPs (including rs551397 and rs800292) and another one SNPs (including rs12124794,rs10737680) and rs1410996 were in strong linkage disequilibrium (D’=1.00).After 50 000 permutations,the GC and AT haplotypes of the first block and the AAC,TCT and ACT haplotypes in the second block were significantly different between AMD patients and controls (P=0.010,0.010,0.001,0.041 and 0.033,respectively).The allel T of rs641153 was a protective factor of AMD (P=0.002,OR=0.273,95%CI:0.120-0.620).
Conclusions
The SNPs rs10737680 and rs1410996 in CFH, rs10490924 of ARMS2 gene and rs11200638 of HTRA1 gene are associated with AMD in Ningxia population.