Association of polymorphisms in C2, CFB and C3 with exudative age-related macular degeneration in a Korean population

Role of complement factor B rs4151667 (L9H) polymorphisms and its interactional role with CFH Y402H and C3 rs2230199 (R102G) risk variants in age-related macular degeneration: a case control study

Background

Age-related Macular Degeneration (AMD) is a complex eye disease, which is genetically associated with different susceptibility loci. We planned to investigate the possible association of Complement Factor B (CFB) rs4151667 (L9H) variants and their possible interaction with Complement Factor H (CFH) Y402H and Complement factor 3 (C3) rs2230199 (R102G) in AMD.

Methods

This case-control association study included 216 advanced type AMD patients and 191 healthy individuals for evaluation. Extracted-DNA samples were genotyped for the polymorphic regions of CFB rs4151667 (L9H), CFH Y402H and C3 rs2230199 (R102G).

Results

The distribution of CFB rs4151667 (L9H) genotypes was not significantly different in the AMD patients compared to that of controls (P = 0.18). The AT genotype frequencies for CFB was non significantly lower in AMD group (6.5% vs. 13.1%, AOR = 0.49, CI = 0.23–1.04, P = 0.064(. The A allele of CFB rs4151667 (L9H) was found to be non-significantly lower in AMD patients. CFB rs4151667 (L9H) had no protective interactional effect against CFH (Y402H) and C3 (R102G) risk variants.

Conclusions

This study showed that the protective role of CFB rs4151667 (L9H) in AMD is not significant and it has no significant protective interactional effect against CFH (Y402H) and C3 (R102G) risk variants.

Complement factor B knockdown by short hairpin RNA inhibits laser-induced choroidal neovascularization in rats

AIM

To evaluate whether recombinant complement factor B (CFB) short hairpin RNA (shRNA) reduces laser-induced choroidal neovascularization (CNV) in rats.

METHODS

Laser-induced rat CNV model was established, and then the animals underwent fundus fluorescence angiography (FFA) and hematoxylin and eosin (HE) staining. On day 3 and 7 after photocoagulation, the expression of CFB and membrane attack complex (MAC) was detected by immunhischemistry. A recombinant CFB-shRNA plasmid was constructed. CFB and scrambled shRNA plasmids were intravenous injected into rats via the tail vein on the day of laser treatment, respectively. On day 7, the incidence of CNV was determined by FFA, and the expression of CFB and vascular endothelial growth factor (VEGF) in retinal pigment epithelium (RPE)/choroidal tissues was detected by immunhischemistry, Western blot and/or semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) in CFB and scrambled shRNA groups. The possible adverse effects of CFB-shRNA injection were assessed by transmission electron microscopy and electroretinography.

RESULTS

FFA and HE results indicated that a laser-induced rat CNV model was successfully established on day 7 after photocoagulation. The expression of CFB and MAC was extremely weak in normal retina and choroid, and increased on day 3 after photocoagulation. However, it started to reduce on day 7. CFB shRNA plasmid was successfully constructed and induced CFB knockdown in the retinal and choroidal tissues. FFA showed CFB knockdown significantly inhibited incidence of CNV in rats. Moreover, CFB knockdown significantly inhibited the expression of VEGF in RPE/choroidal tissues. CFB shRNA caused no obvious side effects in eyes.

CONCLUSION

CFB knockdown significantly inhibits the formation and development of CNV in vivo through reducing the expression of VEGF, which is a potential therapy target. The alternative pathway of complement activation plays an important role in CNV formation.

The effect of complement factor B gene variation on age-related macular degeneration in Iranian patients

Purpose

To determine the possible association of rs4151667 (L9H) complement factor B (CFB) gene with age-related macular degeneration (AMD). The L9H is one of the functional variations of the CFB. CFB gene encodes the most important protein of the complement system.

Methods

Two hundred sixty-six patients with AMD and 194 unrelated age/sex-matched controls were genotyped for CFB gene (rs4151667) using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. All research subjects were selected from three regions of Iran (Tehran, Tabriz, and Gonabad).

Results

The results showed a significant difference between the frequency of non-TT genotype in total patients and controls [odds ratio (OR) = 0.424, P = 0.038]. The analysis for each studied region showed that in patients originating from the Gonabad population, the frequency of TT and non-TT genotypes between patients and the control group were significantly different (OR = 2.894, P = 0.046 for TT genotype and OR = 0.346, P = 0.026 for non-TT genotype). In patients originating from Tabriz population, TT and non-TT genotypes and A allele revealed considerably different frequencies between the patient and control groups (OR = 3.043, P = 0.017; OR = 0.329, P = 0.013 and OR = 0.347, P = 0.048, respectively). Analysis of patients from Tehran also showed that there was a significant difference in the frequency of TT genotype between patients and controls (OR = 2.168, P = 0.04).

Conclusions

The results of the current study indicated a possible protective role for non-TT genotype in L9H variation CFB gene against AMD in a sample of the Iranian population. The region segregation results showed that TT genotype might be a risk factor for susceptibility to AMD.

Complement factor B gene polymorphisms and risk of age-related macular degeneration: A meta-analysis

Objective:

To investigate the potential correlation between complement factor B polymorphisms and age-related macular degeneration.

Methods:

We retrieved relevant articles systematically by searching PubMed and Web of Science databases. The pooled odds ratios and 95% confidence intervals were calculated for five complement factor B polymorphism rs641153, rs4151667, rs1048709, rs2072633, and rs12614 using data from included articles in both random effects and fixed effect models. Subgroup meta-analysis based on age-related macular degeneration type, choroidal neovascular disease (rs641153 and rs4151667), geographic atrophy (rs641153 and rs4151667), and races was also performed.

Results:

In the overall comparison, we observed that the distribution of rs641153 and the risk of age-related macular degeneration were significantly correlated (p < 0.00001). Similar results were obtained in subgroup analysis based on race (Caucasians, p < 0.00001; Asians, p = 0.003) and age-related macular degeneration type (choroidal neovascular disease, p < 0.00001; geographic atrophy, p = 0.04). As for complement factor B rs4151667, the genotypic effects were also demonstrated statistically significant in overall analysis (p < 0.00001) and only in Caucasians diagnosed with choroidal neovascular disease (p = 0.004), but not in Asians. Moreover, no statistically significant correlations between the complement factor B polymorphisms rs1048709 (p = 0.63), rs2072633 (p = 0.72), rs12614 (p = 0.98) and susceptibility to age-related macular degeneration were detected in either overall or subgroup analysis.

Conclusion:

Collectively, we demonstrated that the complement factor B genes rs641153 and rs4151667, but not rs1048709, rs2072633, rs12614, were associated with the susceptibility of age-related macular degeneration and might play predictive roles in future age-related macular degeneration diagnosis. More studies are needed to verify these findings.

Association Between Complement Factor C2/C3/CFB/CFH Polymorphisms and Age-Related Macular Degeneration: A Meta-Analysis

BACKGROUND

Several previous studies have assessed the contribution of polymorphisms in genes encoding the complement factors C2/C3/CFB/CFH with the risk of age-related macular degeneration (AMD), however the results have been inconsistent. We conducted a meta-analysis to systematically review the potential association between complement factor polymorphisms and AMD.

METHODS

Studies that investigated associations between C2 (rs547154 and rs9332739), C3 (rs1047286), CFB (rs4151667 and rs641153), and CFH (rs551397 and rs2274700) polymorphisms and AMD were identified by searching PubMed, EMBASE, Web of Science, and Cochrane Library databases for articles published prior to January 1, 2018. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to evaluate the association between these polymorphisms and AMD using Stata 12.0 software. Q and I² statistics were used to evaluate between-study heterogeneity. Publication bias analyses were conducted using Begg's test. We also conducted an ethnic subgroup analysis.

RESULTS

A total of 53 studies that included data for 53,774 patients and 56,973 healthy controls were evaluated. The pooled ORs for rs551397, rs2274700, rs4151667, rs641153, rs1047286, rs9332739, and rs547154 in the heterozygote model were 0.53 (95% CI: 0.45-0.61), 0.53 (95% CI: 0.40-0.70), 0.54 (95% CI: 0.46-0.63), 0.48 (95% CI: 0.4-0.57), 1.42 (95% CI: 1.22-1.66), 0.5 (95% CI: 0.45-0.56), and 0.52 (95% CI: 0.43-0.62), respectively.

CONCLUSION

Our findings from this analysis confirmed the protective role of C2/CFB/CFH polymorphisms in the development of AMD, but showed that the single nucleotide polymorphism in C3 was a high-risk factor for AMD. The racial analysis results suggested that the effect of variant alleles was stronger in Caucasians than Asians.

Associations of 6p21.3 Region with Age-related Macular Degeneration and Polypoidal Choroidal Vasculopathy

Neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are leading causes of blindness in aging populations. This study was conducted to investigate the associations of chromosome 6p21.3 region, including CFB-SKIV2L-TNXB-FKBPL-NOTCH4 genes, with both neovascular AMD and PCV. Six single nucleotide polymorphisms (SNPs) in this region and two known AMD-associated SNPs in CFH (rs800292) and HTRA1 (rs11200638) were genotyped in a Han Chinese cohort composed of 490 neovascular AMD patients, 419 PCV patients and 1316 controls. Among the SNPs, TNXB rs12153855 and FKBPL rs9391734 conferred an increased susceptibility to neovascular AMD (P = 2.8 × 10⁻⁴ and 0.001, OR = 1.80 and 1.76, respectively), while SKIV2L exerted a protective effect on neovascular AMD (P = 2.2 × 10⁻⁴, OR = 0.49). Rs12153855C and rs9391734A alleles could further increase the susceptibility to AMD in subjects with rs800292, rs11200638 and rs429608 risk alleles. However, only the association of SKIV2L rs429608 remained significant after adjusting for rs800292, rs11200638 and the other 5 SNPs. The protective haplotype AATGAG exhibited significant association with neovascular AMD (permutation P = 0.015, OR = 0.34). None of the SNPs in this region was associated with PCV. Association profiles of 6p21.3 region showed discrepancy between neovascular AMD and PCV, indicating possible molecular and pathological differences between these two retinal disorders.

Copy number variations and gene polymorphisms of complement components in ocular Behcet's disease and Vogt-Koyanagi-Harada syndrome

Complement is involved in many immune-mediated diseases. However, the association of its copy number variations (CNVs) and polymorphisms with Behcet’s disease (BD) and Vogt-Koyanagi-Harada syndrome (VKH) is unknown. We examined copy number and mRNA expression by real-time PCR. Cytokine production by stimulated peripheral blood mononuclear cells (PBMCs) in genotyped individuals was measured by ELISA. The frequencies of having more than two copies of C3 were significantly increased in BD and VKH, whereas CNV of C5 was only associated with BD. Increased frequencies of the GG genotype of C3 rs408290 and C5 rs2269067 were found in BD. No association was observed between C3 and C5 SNPs and VKH. mRNA expression in the high CNV group and GG cases of C3 and C5 was significantly higher compared to other genotypes. Increased interleukin-17 and IFN-γ was observed in the high CNV group and GG genotype cases of C3. Interleukin-17 but not IFN-γ was increased in the high CNV group and GG genotype cases of C5. No effect of C3 or C5 genetic variants was seen on the production of TNF-α, IL-10, IL-1β, MCP-1, IL-6 and IL-8. Our study thus provides further evidence for a role of complement in the pathogenesis of uveitis.

Nonsynonymous single nucleotide polymorphisms in the complement component 3 gene are associated with risk of age-related macular degeneration: a meta-analysis

Nonsynonymous single nucleotide polymorphisms (SNPs) in complement component 3 (CC3) are associated with the risk of age-related macular degeneration (AMD), however, this association is not consistent among studies. To thoroughly address this issue, we performed an updated meta-analysis to evaluate the association between nine SNPs in the CC3 gene and AMD risk. A search was conducted of the PubMed database through 3rd Aug, 2014. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of associations. Based on the search criteria for manuscripts reporting AMD susceptibility related to CC3 in nine SNPs, 57 case-control studies from 22 different articles were retrieved. Significantly positive associations were found for the rs2230199 C/G SNP and AMD in the Caucasian population, as well as for the rs1047286 C/T SNP. Moreover, a relationship between the rs11569536 G/A SNP and AMD was detected. By contrast, a negative association was observed between rs2250656 A/G SNP and AMD risk. The present meta-analysis suggests that these four SNPs in the CC3 gene are potentially associated with the risk of AMD development. Further studies using larger sample sizes and accounting for gene-environment interactions should be conducted to elucidate the role of CC3 gene polymorphisms in AMD risk.

Association of specific genetic polymorphisms with age-related macular degeneration in a northern Chinese population

PURPOSE

The associations between genetic variants located in CFH, CFB, ARMS2 and HTRA1 and the risk of age-related macular degeneration (AMD) in a northern Chinese population were investigated.

METHODS

A case-control association study of 150 AMD patients and 145 ethnicity- and gender-matched controls were recruited. Genomic DNA was prepared from peripheral blood after the participants underwent comprehensive eye examinations. All individuals were genotyped for eight single nucleotide polymorphisms (SNPs) in four specific genes. Genotypic distribution was tested for Hardy-Weinberg equilibrium. Statistical analysis was performed for genotype, allele and haplotype frequencies along with their p values and corresponding odds ratios (OR), 95% confidence intervals (95% CI) and measures of linkage disequilibrium (LD). Bonferroni corrections for multiple comparisons were performed.

RESULTS

Among the SNPs genotyped, p values of seven SNPs were less than 0.05 in the genotypic distributions and allele frequencies between AMD and control subjects. However, after Bonferroni correction, the genotype and allele distributions of two SNPs in CFH (rs10737680, rs1410996), one SNP (rs10490924) in ARMS2 and one SNP (rs11200638) in HTRA1 differed significantly between the controls and AMD patients. Two SNPs were significantly associated with AMD in the allele distributions. They were rs800292 (p(allele) = 0.006, OR [CI] = 1.643[1.155-2.336]) in CFH and rs641153 (p(allele) = 0.002, OR [CI] = 0.273[0.120-0.620]) in CFB. Five haplotypes in CFH significantly predisposed patients to AMD after 50,000 permutations (p = 0.0099, p = 0.0099, p = 0.0013, p = 0.0414 and p = 0.0327).

CONCLUSIONS

Gene variants in CFH, ARMS2 and HTRA1 are related to an increased risk of AMD in a northern Chinese population.

Genetic variants in the SKIV2L gene in exudative age-related macular degeneration in the Japanese population

BACKGROUND

To investigate whether genetic variant in superkiller viralicidic activity 2-like (SKIV2L) gene is associated with exudative age-related macular degeneration (AMD) including neovascular AMD, polypoidal choroidal vasculopathy (PCV), and retinal angiomatous proliferation (RAP).

MATERIALS AND METHODS

A total of 517 patients with exudative AMD comprised of 157patients with neovascular AMD, 333 patients with PCV, and 27patients with RAP, and 205 controls were enrolled in this study. Rs429608 inSKIV2L, rs800292 in complement factor H (CFH), rs10490924 in age-related maculopathy susceptibility2 (ARMS2) gene was genotyped using TaqMan technology. Logistic regression analysis was performed to correlate the risk for exudative AMD with demographic and genetic factors.

RESULTS

The A allele frequency of rs429608 in the SKIV2L gene was significantly higher in controls (13.9%) than in those with neovascular AMD (5.7%, p = 0.002), PCV (7.2%, p = 0.003) and RAP (3.7%, p = 0.0345). After adjusting for age, gender, ARMS2 A69S, and CFHI62V, the A allele of rs429608 was significantly protective against neovascular AMD (odds ratio [OR] 0.24, 95% confidence interval [CI] 0.122-0.484, p < 0.001), PCV (OR 0.43, 95% CI 0.262-0.704, p = 0.001), RAP (OR 0.09, 95% CI 0.014-0.581, p = 0.011).

CONCLUSIONS

A SKIV2L variant was associated with protection against exudative AMD regardless of subtypes in the Japanese population.

Complement C3, C2, and factor B gene polymorphisms and age-related macular degeneration in a Greek cohort study

PURPOSE

To elucidate whether polymorphisms of C2, C3, and CFB genes are major genetic determinants of age-related macular degeneration (AMD) in a Greek population.

METHODS

This was a case-control association study comprising 120 Greek patients with early and late-stage AMD and 140 independent controls of Caucasian origin. All participants were genotyped for rs547154, rs2230199, rs641153, and rs12614 polymorphisms by a combination of PCR and direct DNA sequencing assays.

RESULTS

The frequency of the rs2230199 G allele (minor allele) was significantly higher in patients with AMD in comparison with controls (0.34 vs 0.22, p = 0.0031) and similar to the frequency of other reported populations. There was a significant difference in the frequencies of the rs2230199 genotypes among cases and controls (p = 0.0055). rs2230199 was found to be a significant predictor of advanced AMD status (odds ratio 6.41, confidence interval [CI] 2.72-15.09, p<0.0001; area under the curve 0.706, CI 0.61-0.78, p<0.0001]). For the other single nucleotide polymorphism (SNP) loci, the allele and genotype frequencies did not reach statistical significance. The minor allele frequencies in controls and cases were similar and still much lower than the frequencies reported in other populations.

CONCLUSIONS

The rs547154, rs641153, and rs12614 SNPs were not associated with AMD development in Greek patients. However, this finding should be viewed with caution as the particular polymorphisms presented with very low frequencies in the Greek population. Finally, the replication of the reported associations of C3 with AMD suggests that the presence of the C3 G allele could serve as a high-risk genetic marker for the development of AMD and the progression of the disease to the advanced clinical stage.

Association between complement factor H Val62Ile polymorphism and age-related macular degeneration susceptibility: a meta-analysis

BACKGROUND

An increasing body of studies has assessed the contribution of Val62Ile polymorphism to age-related macular degeneration (AMD) risk, but the exact association still remains uncertain. This meta-analysis was undertaken in order to further characterize the potential association between Val62Ile polymorphism and AMD risk in four different ethnic populations.

METHODS

A meta-analysis was performed using data available from 16 case-control studies evaluating correlation between the Val62Ile polymorphism and AMD in Caucasian, Chinese, Japanese and South Korean populations. Data extraction and study quality assessment were performed in duplicate. Summary odds ratios (ORs) and 95% confidence intervals (CIs) of allele contrast and genotype contrast were estimated using the random-effects model. The Q-statistic test was used to identify heterogeneity, and the funnel plot was adopted to evaluate publication bias.

RESULTS

Sixteen studies involving a total of 11,400 subjects based on the search criteria were included in the meta-analysis. In overall populations, the Val62Ile polymorphism seemed to be associated with AMD (ORAA vs. GG=0.40, 95% CI=0.28-0.59; ORAA+GA vs. GG=0.72, 95% CI=0.64-0.80; ORAA vs. GC+GG=0.50, 95% CI=0.36-0.70; ORA vs. G=0.68, 95% CI=0.58-0.78; ORGA vs. GG=0.71, 95% CI=0.65-0.77). Similarly, subgroup analysis also revealed that this polymorphism was related to AMD in all ethnicities.

CONCLUSIONS

This meta-analysis suggested that Val62Ile polymorphism was associated with susceptibility to AMD.

Complement factor B polymorphism (rs641153) and susceptibility to age-related macular degeneration: evidence from published studies

AIM

To determine whether single nucleotide polymorphism (SNP) rs641153 is associated with the risk of age-related macular degeneration (AMD), we performed a systematic meta-analysis of 15 eligible studies. SNP in the complement factor B (CFB) gene is considered to have significant association with AMD susceptibility, but there is great discrepancy in these results.

METHODS

The eligible studies were identified by searching the databases of PubMed, EMBASE, and Web of Science. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association. All data were analyzed using Stata software.

RESULTS

The association between rs641153 and AMD risk was statistically significant under the homozygous model (AA vs GG:OR=0.26, 95%CI=0.15-0.45, P h=0.973, I (2)=0.0%, fixed effects), dominant model (AA+GA vs GG:OR=0.49, 95%CI=0.40-0.59, P h=0.004, I (2)=56.4%, random effects) and recessive model (AA vs GA+GG:OR=0.30, 95%CI=0.17-0.51, P h=0.983, I (2)=0.0%, fixed effects). The same results were also observed in the stratified analyses by ethnicity, source of control and sample size.

CONCLUSION

Our meta-analysis suggests that rs641153 in the CFB gene may play a protective role in AMD susceptibility, the late AMD in particular, both in Caucasians and in Asians.

Complement factor B polymorphism and the phenotype of early age-related macular degeneration

PURPOSE

Age-related macular degeneration (AMD) has been associated with a number of polymorphisms in genes in the complement pathway. We examined the potential genotype-phenotype correlation of complement factor B (CFB) (R32Q) polymorphisms in Caucasian patients with AMD.

METHODS

Data from a Central European cohort of 349 patients with early AMD in at least one eye were analyzed for potential associations of the CFB (R32Q/rs641153) polymorphism with phenotypic features of early AMD. Early AMD was classified according to the International Classification and Grading System into predominant drusen size, largest drusen, drusen covered surface, central or ring-like location, peripheral drusen, and pigmentary changes. The potential association with single nucleotide polymorphisms on CFB (R32Q/rs641153) was evaluated for all patients, corrected for age, sex, and the polymorphisms of CFH (Y402H) and ARMS2 (A69S).

RESULTS

CFB (R32Q) polymorphisms showed a significant association with smaller drusen size (largest drusen ≤ 250 µm, p = 0.021, predominant drusen ≤ 125 µm, p = 0.016), with smaller surface covered by drusen (≤ 10%; p = 0.02), and with more frequent occurrence of peripheral drusen (p = 0.007). No association was found for pigmentary changes.

CONCLUSIONS

The CFB (R32Q) polymorphism was associated with AMD characterized by small drusen only, and appeared to be protective of large drusen (OR 0.48/0.45) and of larger drusen covered area (OR 0.34). Furthermore, peripheral drusen were more frequently found (OR 2.27). This result supports the role of complement components and their polymorphisms in drusen formation and may enable a better understanding of AMD pathogenesis.

Y402H polymorphism in complement factor H and age-related macular degeneration in the Tunisian population

To evaluate a possible association between the complement factor H (CFH) Y402H polymorphism and susceptibility to age-related macular degeneration (AMD) in the Tunisian population, as well as the impact of the genotype distribution among different phenotypes and the response to treatment with intravitreal bevacizumab, exon 9 of CFH was analyzed for the Y402H polymorphism by direct sequencing in 135 healthy controls and 127 sporadic unrelated AMD patients classified into the following groups: 12 atrophic AMD (group G1), 115 exudative AMD (G2) and 10 AMD patients who had fibrovascular scarring (G3) that did not allow a precise grading of the phenotype. Seventy patients in G2 were treated with 1.25 mg intravitreal bevacizumab at 6-week intervals until choroidal neovascularization (CNV) was no longer active. The frequency of the CFH 402H allele was significantly higher in AMD patients than in controls (p = 2.62 × 10(-16)). However, subgroup analysis does not reveal any association between the variant allele H and phenotypes of AMD or CNV. Also, there was no significant difference in response to bevacizumab treatment according to Y402H CFH genotype (p = 0.59). A strong association of the 402H allele with susceptibility to AMD in the Tunisian population was confirmed; however, this variant does not appear to be involved in the clinical progression of this disease or in the postintravitreal bevacizumab response.

Association between polymorphisms of complement pathway genes and age-related macular degeneration in a Chinese population

PURPOSE

We assessed the association between complement pathway genes and age-related macular degeneration (AMD) in a Chinese population.

METHODS

In a case-control study, 165 AMD patients and 216 unrelated controls were recruited from two hospitals in central China. We selected and genotyped six single nucleotide polymorphisms (SNPs) of four complement pathway genes, including rs800292 and rs1410996 of complement H (CFH), rs9332739 of complement 2 (C2), rs4151667 of complement factor B (CFB), and rs2241394 and rs2230199 of complement 3 (C3). The associations between SNPs and AMD, adjusted by age and sex, were assessed by using logistic regression models and haplotype association analysis.

RESULTS

In our study, two SNPs of CFH and their haplotypes were associated significantly with AMD, and the adjusted odd ratios (ORs) were 2.45 (95% confidence interval [CI] 1.25-4.79) for rs800292 (genotype GG versus AA), 2.49 (95% CI 1.24-5.00) for rs1410996 (genotype TT versus CC), and 4.45 (95% CI 2.32-8.55) for haplotype block of rs800292-rs1410996 (haplotype G-C versus A-C), respectively. The haplotype of C2/CFB also was associated significantly with AMD, and the adjusted OR was 8.86 (95% CI 1.88-41.69) for the haplotype block of rs9332739-rs4151667 (haplotype G-A versus G-T), though no relationship was found in genotype association analysis of the two SNPs of C2/CFB. With the sample size of our study, no relationship was found for AMD and the two SNPs of C3.

CONCLUSIONS

Gene variants in CFH and C2/CFB contribute to AMD in the Chinese population.

Associations of the C2-CFB-RDBP-SKIV2L locus with age-related macular degeneration and polypoidal choroidal vasculopathy

PURPOSE

To investigate the associations of the C2-CFB-RDBP-SKIV2L region with neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV).

DESIGN

Cross-sectional, case-control association study.

PARTICIPANTS

A Chinese case-control group of 200 neovascular AMD patients, 233 PCV patients, and 275 control subjects.

METHODS

An association analysis was performed of the C2-CFB-RDBP-SKIV2L locus with both neovascular AMD and PCV in a Chinese population using 19 haplotype-tagging single nucleotide polymorphisms (SNPs) and 6 previously reported SNPs across the C2-CFB-RDBP-SKIV2L region. All SNPs were genotyped using the TaqMan genotyping technology (TaqMan; Applied Biosystems [ABI], Foster City, CA).

MAIN OUTCOME MEASURES

Allele and haplotype frequencies of the SNPs in the C2-CFB-RDBP-SKIV2L region.

RESULTS

The SKIV2L SNPs rs429608 and rs453821 were significantly associated with neovascular AMD (P = 7.39 × 10(-5); odds ratio [OR], 0.22; 95% confidence interval [CI], 0.10-0.50; and P = 0.001; OR, 0.38; 95% CI, 0.21-0.70, respectively), whereas borderline associations were detected for C2 rs547154 (P = 0.002) and RDBP rs760070 (P = 0.003). Conditional haplotype analysis revealed that SKIV2L rs429608 could account fully for the global haplotype association identified in this region. The association of SKIV2L rs429608 with neovascular AMD remained significant after adjusting for CFH rs800292 and HTRA1 rs11200638. No individual SNP or haplotype was associated significantly with PCV.

CONCLUSIONS

In this concurrent investigation of the associations of the entire C2-CFB-RDBP-SKIV2L region with neovascular AMD and PCV, the results suggested that SKIV2L is a likely causal gene for neovascular AMD, conferring a significant protective effect independent of CFH and HTRA1. These data do not support a significant role of this region in PCV, suggesting different molecular mechanisms between neovascular AMD and PCV.