Replication Study Confirms Link between TSPAN18 Mutation and Schizophrenia in Han Chinese

Schizophrenia (SCZ) is a severe psychiatric disorder associated with many different risk factors, both genetic and environmental. A recent genome-wide association study (GWAS) of Han Chinese identified three single-nucleotide polymorphisms (SNPs rs11038167, rs11038172, and rs835784) in the tetraspanins gene TSPAN18 as possible susceptibility loci for schizophrenia. Hoping to validate these findings, we conducted a case-control study of Han Chinese with 1093 schizophrenia cases and 1022 healthy controls. Using the LDR-PCR method to genotype polymorphisms in TSPAN18, we found no significant differences (P>0.05) between patients and controls in either the allele or genotype frequency of the SNPs rs11038167 and rs11038172. We did find, however, that the frequency of the ‘A’ allele of SNP rs835784 is significantly higher in patients than in controls. We further observed a significant association (OR  = 1.197, 95%CI  = 1.047–1.369) between risk for SCZ and this ‘A’ allele. These results confirm the significant association, in Han Chinese populations, of increased SCZ risk and the variant of the TSPAN18 gene containing the ‘A’ allele of SNP rs835784.     

A Genetic Variant rs1801274 in FCGR2A as a Potential Risk Marker for Kawasaki Disease: A Case-Control Study and Meta-Analysis

Objectives

Recent genome-wide association study found rs1801274, a functional single nucleotide polymorphism (SNP) in IgG receptor gene FCGR2A, was associated with increased risk of Kawasaki disease (KD). However, subsequent studies on the role of this SNP were limited and controversial.

Methods

A case-control study was conducted in a Chinese Han population including 428 KD patients and 493 controls to examine the association between rs1801274 and KD susceptibility. A meta-analysis was performed in combination with the relevant published studies to further clarify such an association.

Results

Our case-control study found that rs1801274 was significantly associated with increased risk of KD in the Chinese Han population, with an odds ratio (OR) of 1.58 (95% CI = 0.96–2.62) for the GA genotype and 1.93 (95% CI = 1.16–3.19) for the AA genotype compared with the GG genotype. The result of meta-analysis further demonstrated that the A allele of rs1801274 was significantly correlated with KD risk under the allelic model (OR = 1.35, 95% CI = 1.27–1.44) without heterogeneity by fixed-effects model analysis (Q = 17.30, p = 0.139). Moreover, sensitivity analysis supported the robustness of this meta-analysis.

Conclusion

These results further confirm that rs1801274 in the FCGR2A gene is significantly associated with increased risk of KD.     

E-Selectin Gene Polymorphisms and Essential Hypertension in Asian Population: An Updated Meta-Analysis

Objective

Epidemiological studies have shown that E-selectin gene polymorphisms (A561C and C1839T) may be associated with essential hypertension (EH), but the results are conflicting in different ethnic populations. Thus, we performed this meta-analysis to investigate a more authentic association between E-selectin gene polymorphisms and the risk of EH.

Methods

We searched the relevant studies for the present meta-analysis from the following electronic databases: PubMed, Embase, Cochrane Library, Google Scholar, Web of Science, Wanfang Data, and China National Knowledge Infrastructure (CNKI). Odds ratios (OR) with 95% confidence interval (CI) were used to evaluate the strength of the association between E-selectin gene polymorphisms and EH susceptibility. The pooled ORs were performed for dominant model, allelic model and recessive model. The publication bias was examined by Begg’s funnel plots and Egger’s test.

Results

A total of eleven studies met the inclusion criteria. All studies came from Asians. Ten studies (12 cohorts) evaluated the A561C polymorphism and EH risk, including 2,813 cases and 2,817 controls. The pooled OR was 2.280 (95%CI: 1.893–2.748, P<0.001) in dominant model, 5.284 (95%CI: 2.679–10.420, P<0.001) in recessive model and 2.359 (95%CI: 1.981–2.808, P = 0.001) in allelic model. Four studies (six cohorts) evaluated C1839T polymorphism and EH risk, including 1,700 cases and 1,681 controls. The pooled OR was 0.785 (95%CI: 0.627–0.983, P = 0.035) in dominant model, 1.250 (95%CI: 0.336–4.652, P = 0.739) in recessive model and 0.805 (95%CI: 0.649–0.999, P = 0.049) in allelic model.

Conclusion

The current meta-analysis concludes that the C allele of E-selectin A561C gene polymorphism might increase the EH risk in Asian population, whereas the T allele of E-selectin C1839T gene polymorphism might decrease the EH risk.     

Individual Correlates of Podoconiosis in Areas of Varying Endemicity: A Case-Control Study

Background

Podoconiosis is a non-filarial form of elephantiasis resulting in lymphedema of the lower legs. Previous studies have suggested that podoconiosis arises from the interplay of individual and environmental factors. Here, our aim was to understand the individual-level correlates of podoconiosis by comparing 460 podoconiosis-affected individuals and 707 unaffected controls.

Methods/principal findings

This was a case-control study carried out in six kebeles (the lowest governmental administrative unit) in northern Ethiopia. Each kebele was classified into one of three endemicity levels: ‘low’ (prevalence <1%), ‘medium’ (1–5%) and ‘high’ (>5%). A total of 142 (30.7%) households had two or more cases of podoconiosis. Compared to controls, the majority of the cases, especially women, were less educated (OR = 1.7, 95% CI = 1.3 to 2.2), were unmarried (OR = 3.4, 95% CI = 2.6–4.6) and had lower income (t = −4.4, p<0.0001). On average, cases started wearing shoes ten years later than controls. Among cases, age of first wearing shoes was positively correlated with age of onset of podoconiosis (r = 0.6, t = 12.5, p<0.0001). Among all study participants average duration of shoe wearing was less than 30 years. Between both cases and controls, people in ‘high’ and ‘medium’ endemicity kebeles were less likely than people in ‘low’ endemicity areas to ‘ever’ have owned shoes (OR = 0.5, 95% CI = 0.4–0.7).

Conclusions

Late use of shoes, usually after the onset of podoconiosis, and inequalities in education, income and marriage were found among cases, particularly among females. There were clustering of cases within households, thus interventions against podoconiosis will benefit from household-targeted case tracing. Most importantly, we identified a secular increase in shoe-wearing over recent years, which may give opportunities to promote shoe-wearing without increasing stigma among those at high risk of podoconiosis.     

Association between CD14 Gene C-260T Polymorphism and Inflammatory Bowel Disease: A Meta-Analysis

Background

The gene encoding CD14 has been proposed as an IBD-susceptibility gene with its polymorphism C-260T being widely evaluated, yet with conflicting results. The aim of this study was to investigate the association between this polymorphism and IBD by conducting a meta-analysis.

Methodology/Principal Findings

Seventeen articles met the inclusion criteria, which included a total of 18 case-control studies, including 1900 ulcerative colitis (UC) cases, 2535 Crohn''s disease (CD) cases, and 4004 controls. Data were analyzed using STATA software. Overall, association between C-260T polymorphism and increased UC risk was significant in allelic comparison (odds ratio [OR]  = 1.21, 95% confidence interval [CI]: 1.02–1.43; P = 0.027), homozygote model (OR  = 1.44, 95% CI: 1.03–2.01; P = 0.033), as well as dominant model (OR  = 1.36, 95% CI: 1.06–1.75; P = 0.016). However, there was negative association between this polymorphism and CD risk across all genetic models. Subgroup analyses by ethnicity suggested the risk-conferring profiles of -260T allele and -260 TT genotype with UC in Asians, but not in Caucasians. There was a low probability of publication bias.

Conclusions/Significance

Expanding previous results of individual studies, our findings demonstrated that CD14 gene C-260T polymorphism might be a promising candidate marker in susceptibility to UC, especially in Asians.     

Genetic Variations of IL-12B,IL-12Rβ1, IL-12Rβ2 in Behcet's Disease and VKH Syndrome

Purpose

To investigate the associations of single nucleotide polymorphisms (SNPs) of three genes (IL-12B, IL-12Rβ1 and IL-12Rβ2) in Behcet''s disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in a Chinese Han population.

Methods

A total of 806 BD cases, 820 VKH patients, and 1600 healthy controls were involved in this study. The first investigation included 400 BD patients, 400 VKH cases, and 600 healthy individuals. A second confirmatory study included a separate set of 406 BD patients, 420 VKH cases and another 1000 normal controls. Genotyping was carried out by PCR-restriction fragment length polymorphism assay and results were validated by using direct sequencing. The χ2 test was performed to compare the allele and genotype frequencies between cases and healthy controls.

Results

This study comprised two phases. In the first phase study, a significantly increased frequency of the rs3212227/IL-12B genotype CC and C allele was found in BD patients as compared to controls (Bonferroni corrected p value (p_c) = 0.009, OR 1.8; p_c = 0.024, OR 1.3, respectively). Moreover, the frequency of the C allele of rs3212227/IL-12B was also significantly increased in VKH patients (p_c = 0.012, OR 1.3, 95% CI 1.1 to 1.6). No associations were found for the other seven tested SNPs either in BD or VKH disease. The second study as well as the combined data confirmed the significant association of rs3212227/IL-12B with BD (CC genotype: combined p_c = 6.3×10⁻⁷, OR = 1.8; C allele: combined p_c = 2.0×10⁻⁵, OR = 1.3, respectively) and the C allele frequency of rs3212227/IL-12B as the risk factor to VKH patients (combined p_c = 2.5×10⁻⁵, OR 1.3, 95% CI 1.2 to 1.5).

Conclusions

Our study revealed that the IL-12B gene is involved both in the susceptibility to BD as well as VKH syndrome.     

Genetic Variation in the Familial Mediterranean Fever Gene (MEFV) and Risk for Crohn's Disease and Ulcerative Colitis

Background and Aims

The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1β processing. Pyrin has been shown to interact with the gene product of NLRP3, NALP3/cryopyrin, also an important active member of the inflammasome. The NLRP3 region was recently reported to be associated with Crohn''s disease (CD) susceptibility. We therefore sought to evaluate MEFV as an inflammatory bowel disease (IBD) susceptibility gene.

Methodology and Results

MEFV colonic mucosal gene expression was significantly increased in experimental colitis mice models (TNBS p<0.0003; DSS p<0.006), in biopsies from CD (p<0.02) and severe ulcerative colitis (UC) patients (p<0.008). Comprehensive genetic screening of the MEFV region in the Belgian exploratory sample set (440 CD trios, 137 UC trios, 239 CD cases, 96 UC cases, and 107 healthy controls) identified SNPs located in the MEFV 5′ haplotype block that were significantly associated with UC (rs224217; p = 0.003; A allele frequency: 56% cases, 45% controls), while no CD associations were observed. Sequencing and subsequent genotyping of variants located in this associated haplotype block identified three synonymous variants (D102D/rs224225, G138G/rs224224, A165A/rs224223) and one non-synonymous variant (R202Q/rs224222) located in MEFV exon 2 that were significantly associated with UC (rs224222: p = 0.0005; A allele frequency: 32% in cases, 23% in controls). No consistent associations were observed in additional Canadian (256 CD trios, 91 UC trios) and Scottish (495 UC, 370 controls) sample sets. We note that rs224222 showed marginal association (p = 0.012; G allele frequency: 82% in cases, 70% in controls) in the Canadian sample, but with a different risk allele. None of the NLRP3 common variants were associated with UC in the Belgian-Canadian UC samples and no significant interactions were observed between NLRP3 and MEFV that could explain the observed flip-flop of the rs224222 risk allele.

Conclusion

The differences in association levels observed between the sample sets may be a consequence of distinct founder effects or of the relative small sample size of the cohorts evaluated in this study. However, the results suggest that common variants in the MEFV region do not contribute to CD and UC susceptibility.     

Limited Evidence for Parent-of-Origin Effects in Inflammatory Bowel Disease Associated Loci

Background

Genome-wide association studies of two main forms of inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), have identified 99 susceptibility loci, but these explain only ∼23% of the genetic risk. Part of the ‘hidden heritability’ could be in transmissible genetic effects in which mRNA expression in the offspring depends on the parental origin of the allele (genomic imprinting), since children whose mothers have CD are more often affected than children with affected fathers. We analyzed parent-of-origin (POO) effects in Dutch and Indian cohorts of IBD patients.

Methods

We selected 28 genetic loci associated with both CD and UC, and tested them for POO effects in 181 Dutch IBD case-parent trios. Three susceptibility variants in NOD2 were tested in 111 CD trios and a significant finding was re-evaluated in 598 German trios. The UC-associated gene, BTNL2, reportedly imprinted, was tested in 70 Dutch UC trios. Finally, we used 62 independent Indian UC trios to test POO effects of five established Indian UC risk loci.

Results

We identified POO effects for NOD2 (L1007fs; OR = 21.0, P-value = 0.013) for CD; these results could not be replicated in an independent cohort (OR = 0.97, P-value = 0.95). A POO effect in IBD was observed for IL12B (OR = 3.2, P-value = 0.019) and PRDM1 (OR = 5.6, P-value = 0.04). In the Indian trios the IL10 locus showed a POO effect (OR = 0.2, P-value = 0.03).

Conclusions

Little is known about the effect of genomic imprinting in complex diseases such as IBD. We present limited evidence for POO effects for the tested IBD loci. POO effects explain part of the hidden heritability for complex genetic diseases but need to be investigated further.     

Dissecting the Gene Dose-Effects of the APOE ε4 and ε2 Alleles on Hippocampal Volumes in Aging and Alzheimer’s Disease

Objective

To investigate whether there is a specific dose-dependent effect of the Apolipoprotein E (APOE) ε4 and ε2 alleles on hippocampal volume, across the cognitive spectrum, from normal aging to Alzheimer’s Disease (AD).

Materials and Methods

We analyzed MR and genetic data on 662 patients from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database–198 cognitively normal controls (CN), 321 mild-cognitive impairment (MCI) subjects, and 143 AD subjects–looking for dose-dependent effects of the ε4 and ε2 alleles on hippocampal volumes. Volumes were measured using a fully-automated algorithm applied to high resolution T1-weighted MR images. Statistical analysis consisted of a multivariate regression with repeated-measures model.

Results

There was a dose-dependent effect of the ε4 allele on hippocampal volume in AD (p = 0.04) and MCI (p = 0.02)–in both cases, each allele accounted for loss of >150 mm³ (approximately 4%) of hippocampal volume below the mean volume for AD and MCI subjects with no such alleles (Cohen’s d = −0.16 and −0.19 for AD and MCI, respectively). There was also a dose-dependent, main effect of the ε2 allele (p<0.0001), suggestive of a moderate protective effect on hippocampal volume–an approximately 20% per allele volume increase as compared to CN with no ε2 alleles (Cohen’s d = 0.23).

Conclusion

Though no effect of ε4 was seen in CN subjects, our findings confirm and extend prior data on the opposing effects of the APOE ε4 and ε2 alleles on hippocampal morphology across the spectrum of cognitive aging.     

A Meta-Analysis of the Effects of the 5-Hydroxytryptamine Transporter Gene-Linked Promoter Region Polymorphism on Susceptibility to Lifelong Premature Ejaculation

Objective

Premature ejaculation (PE) has been reported as the most common male sexual dysfunction with global prevalence rates estimated at approximately 30%. The neurobiogenesis of ejaculation is very complex and involves the serotoninergic (5-hydroxytryptamine, 5-HT) system. Recently, genetic polymorphisms located on SLC6A4 gene codifying for 5-HT transporter (5-HTT), the major regulator of serotonic neurotransmission, have been linked with the pathogenesis and risk of PE. Apparently studies of this type of polymorphism in PE have show conflicting results.

Methods

A meta-analysis was performed that are available in relation with 5-HTT gene-linked promoter region (5-HTTLPR) polymorphism and the risk of lifelong PE (LPE) in men to clarify this relationship. We searched Pubmed and Embase (last search updated on Aug 2012) using ‘premature ejaculation’, ‘polymorphism or variant’, ‘genotype’, ‘ejaculatory function’, and ‘rapid ejaculation’ as keywords and reference lists of studies corresponded to the inclusion criteria for meta-analysis. These studies involved the total number of 481 LPE men and 466 health control men subjects. Odds ratio (OR) and 95% confidence intervals (CIs) were used to evaluate this relationship.

Results

In the overall analysis, significant associations between LPE risk and 5-HTTLPR polymorphism were found (L-allele vs. S-allele OR = 0.86, 95% CI = 0.79–0.95, P = 0.002; LL vs. SS: OR = 0.80, 95% CI = 0.68–0.95, P = 0.009; LS vs. SS: OR = 0.85, 95% CI = 0.76–0.97, P = 0.012 and LL+LS vs. SS: OR = 0.88, 95% CI = 0.81–0.95, P = 0.002). Moreover, in subgroup analysis based on ethnicity, similar significant associations were detected. The Egger’s test did not reveal presence of a publication bias.

Conclusions

Our investigations demonstrate that 5-HTTLPR (L>S) polymorphism might protect men against LPE risk. Further studies based on larger sample size and gene-environment interactions should be conducted the role of 5-HTTLPR polymorphism and LPE risk.     

Overweight Associated with Increased Risk of Erosive Esophagitis in a Non-Obese Taiwanese Population

Objective

To investigate the relationship between overweight and erosive esophagitis (EE) in a non-obese Taiwanese population.

Design and Methods

A total of 7,352 subjects (non-obese, 5,826; obese, 1,526) from a health examination center at National Cheng Kung University Hospital were enrolled. Central obesity was defined by a waist circumference (WC) ≥90 cm in male and 80 cm in female. Overweight was defined as body mass index (BMI) of 24–26.9 kg/m², and general obesity as BMI ≥27 kg/m². The Los Angeles classification was adopted to determine the presence of EE.

Results

There were significant differences in the prevalence of central obesity and different BMI status between subjects with and without EE in total and non-obese population. In total population, multivariate analyses revealed central obesity (OR, 1.17, 95% CI, 1.02–1.34, p = 0.021) and being obese (OR, 1.28, 95% CI, 1.07–1.52, p = 0.007)/overweight (OR, 1.25, 95% CI, 1.08–1.45, p = 0.003) had positive associations with EE in different model, respectively. When considering the joint effect of central obesity and BMI status, overweight (OR, 1.22; 95% CI, 1.04–1.44; p = 0.016) remained as an independent associated factor of EE but central obesity (OR, 1.06; 95% CI, 0.89–1.26; p = 0.549)/being obese (OR, 1.22; 95% CI, 0.98–1.53; p = 0.082) did not. As for non-obese group, separate model showed central obesity (OR, 1.19, 95% CI, 1.00–1.40, p = 0.046) and overweight (OR, 1.24; 95% CI, 1.07–1.44, p = 0.005) was positively associated with EE, respectively. However, being overweight (OR, 1.20; 95% CI, 1.02–1.42, p = 0.030) but not central obesity (OR, 1.08; 95% CI, 0.90–1.31; p = 0.398) was positively related to EE with considering the effect of overweight and central obesity simultaneously.

Conclusion

Overweight effect on EE was more detrimental than central obesity in non-obese subjects. In addition, male gender, hiatus hernia and alcohol use were also associated with increased risk of EE.     

CD40: Novel Association with Crohn's Disease and Replication in Multiple Sclerosis Susceptibility

Background

A functional polymorphism located at −1 from the start codon of the CD40 gene, rs1883832, was previously reported to disrupt a Kozak sequence essential for translation. It has been consistently associated with Graves'' disease risk in populations of different ethnicity and genetic proxies of this variant evaluated in genome-wide association studies have shown evidence of an effect in rheumatoid arthritis and multiple sclerosis (MS) susceptibility. However, the protective allele associated with Graves'' disease or rheumatoid arthritis has shown a risk role in MS, an effect that we aimed to replicate in the present work. We hypothesized that this functional polymorphism might also show an association with other complex autoimmune condition such as inflammatory bowel disease, given the CD40 overexpression previously observed in Crohn''s disease (CD) lesions.

Methodology

Genotyping of rs1883832C>T was performed in 1564 MS, 1102 CD and 969 ulcerative colitis (UC) Spanish patients and in 2948 ethnically matched controls by TaqMan chemistry.

Principal Findings

The observed effect of the minor allele rs1883832T was replicated in our independent Spanish MS cohort [p = 0.025; OR (95% CI) = 1.12 (1.01–1.23)]. The frequency of the minor allele was also significantly higher in CD patients than in controls [p = 0.002; OR (95% CI) = 1.19 (1.06–1.33)]. This increased predisposition was not detected in UC patients [p = 0.5; OR (95% CI) = 1.04 (0.93–1.17)].

Conclusion

The impact of CD40 rs1883832 on MS and CD risk points to a common signaling shared by these autoimmune conditions.     

Genetic Polymorphisms of GSTM1, GSTT1, and GSTP1 with Prostate Cancer Risk: A Meta-Analysis of 57 Studies

Background and Objectives

The GSTM1, GSTT1 and GSTP1 polymorphisms might be involved in inactivation of procarcinogens that contribute to the genesis and progression of cancers. However, studies investigating the association between GSTM1, GSTT1 or GSTP1 polymorphisms and prostate cancer (PCa) risk report conflicting results, therefore, we conducted a meta-analysis to re-examine the controversy.

Methods

Published literature from PubMed, Embase, Google Scholar and China National Knowledge Infrastructure (CNKI) were searched (updated to June 2, 2012). According to our inclusion criteria, studies that observed the association between GSTM1, GSTT1 or GSTP1 polymorphisms and PCa risk were included. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of PCa associated with GSTM1, GSTT1 and GSTP1 polymorphisms.

Results

Fifty-seven studies involving 11313 cases and 12934 controls were recruited. The overall OR, which was 1.2854 (95% CI = 1.1405–1.4487), revealed a significant risk of PCa and GSTM1 null genotype, and the similar results were observed when stratified by ethnicity and control source. Further, the more important is that the present study first reported the high risks of PCa for people who with dual null genotype of GSTM1 and GSTT1 (OR = 1.4353, 95% CI = 1.0345–1.9913), or who with GSTT1 null genotype and GSTP1 A131G polymorphism (OR = 1.7335, 95% CI = 1.1067–2.7152). But no association was determined between GSTT1 null genotype (OR = 1.102, 95% CI = 0.9596–1.2655) or GSTP1 A131G polymorphism (OR = 1.0845, 95% CI = 0.96–1.2251) and the PCa risk.

Conclusions

Our meta-analysis suggested that the people with GSTM1 null genotype, with dual null genotype of GSTM1 and GSTT1, or with GSTT1 null genotype and GSTP1 A131G polymorphism are associated with high risks of PCa, but no association was found between GSTT1 null genotype or GSTP1 A131G polymorphism and the risk of PCa. Further rigorous analytical studies are highly expected to confirm our conclusions and assess gene-environment interactions with PCa risk.     

Association of CYP2A6*4 with Susceptibility of Lung Cancer: A Meta-Analysis

ObjectivesTo assess the association between the variant of Cytochrome P450 2A6 whole gene deletion (CYP2A6*4) polymorphism and risk of lung cancer.MethodsTwo investigators independently searched the PubMed, Elsevier, EMBASE, Web of Science, Wiley Online Library and Chinese National Knowledge Infrastructure (CNKI). Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for CYP2A6*4 and lung cancer were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.ResultsThis meta-analysis included seven eligible studies, which included 2524 lung cancer cases and 2258 controls (cancer–free). Overall, CYP2A6*4 was associated with the risk of lung cancer (allele*4 vs. allele non-*4, pooled OR  = 0.826, 95% CI  = 0.725−0.941, P-value  = 0.004). When stratifying for population, significant association was observed in Asian (additive model, pooled OR  = 0.794, 95% CI  = 0.694−0.909, P-value  = 0.001; dominant model, pooled OR  = 0.827, 95% CI  = 0.709−0.965, P-value  = 0.016; recessive model (pooled OR  = 0.444, 95% CI  = 0.293−0.675, P-value <0.0001). In the overall analysis, a comparably significant decrease in the frequency of *4/*4 genotype was detected between cases and controls in Asian while no *4/*4 genotype was detected in Caucasian in collected data.ConclusionThis meta-analysis suggests that the CYP2A6*4 polymorphism is associated with susceptibility of lung cancer in Asian. The whole gene deletion of CYP2A6 may decrease the risk of lung cancer in Asian samples.     

Associations between Genetic Polymorphisms in IL-33, IL1R1 and Risk for Inflammatory Bowel Disease

Background

Recent evidence suggests that the IL-33/IL1RL1 axis plays a critical role in several autoimmune and inflammatory disorders; however, its mechanistic role in inflammatory bowel disease (IBD) has not been clearly defined. We investigated the contribution of IL-33 and IL1RL1 polymorphisms to IBD risk, and possible correlations with phenotype in an Italian cohort of adult and pediatric patients.

Methods

We evaluated the association of six SNPs in IL-33 and IL1RL1 genes, in 805 Crohn’s disease (CD), 816 ulcerative colitis (UC), and 752 controls, using Taqman. IL-33 and IL1RL1 mRNA expression was also analyzed.

Results

Significant allele and genotype associations with IL-33 rs3939286 were found in CD (P = 0.004; P = 0.035) and UC patients (P = 0.002; P = 0.038). After stratifying the cohort for age at diagnosis, the differences remained significant only in the IBD adult-onset. Significant associations were also obtained in CD patients with two IL1RL1 polymorphisms (rs13015714 and rs2058660, P<0.015). By combining homo- and heterozygous carriers of the rs13015714 risk allele, differences were still significant for both CD adult- and pediatric-onset. Upon genotype-phenotype evaluation, an increased frequency of extensive colitis in adult UC (P = 0.019) and in steroid-responsive pediatric patients (P = 0.024) carrying the IL-33 rs3939286 risk genotype, was observed. mRNA expression of IL-33 and IL1RL1 in inflamed IBD biopsy samples was significantly increased.

Conclusions

Common IL-33 and IL1RL1 polymorphisms contribute to the risk of IBD in an Italian cohort of adult and pediatric patients, with some influence on sub-phenotypes.     

Functional Promoter -94 ins/del ATTG Polymorphism in NFKB1 Gene Is Associated with Bladder Cancer Risk in a Chinese Population

Background

A functional -94 insertion/deletion polymorphism (rs28362491) in the promoter of the NFKB1 gene was reported to influence NFKB1 expression and confer susceptibility to different types of cancer. This study aims to determine whether the polymorphism is associated with risk of bladder cancer.

Materials and methods

TaqMan assay was used to determine genotype among 609 cases and 640 controls in a Chinese population. Logistic regression was used to assess the association between the polymorphism and bladder cancer risk, and quantitative real-time polymerase chain reaction was used to determine NFKB1 mRNA expression.

Results

Compared with the ins/ins/ins/del genotypes, the del/del genotype was associated with a significantly increased risk of bladder cancer [adjusted odd ratio (OR)  = 1.92, 95% confidence interval (CI)  = 1.42–2.59]. The increased risk was more prominent among subjects over 65 years old (OR  = 2.37, 95% CI  = 1.52–3.70), male subjects (OR  = 1.97, 95% CI = 1.40–2.79) and subjects with self-reported family history of cancer (OR  = 3.59, 95% CI  = 1.19–10.9). Furthermore, the polymorphism was associated with a higher risk of developing non-muscle invasive bladder cancer (OR  = 2.07, 95% CI  = 1.51–2.85), grade 1 bladder cancer (OR  = 2.40, 95% CI  = 1.68–3.43), single tumor bladder cancer (OR  = 2.04, 95% CI  = 1.48–2.82) and smaller tumor size bladder cancer (OR  = 2.10, 95% CI  = 1.51–2.92). The expression of NFKB1 mRNA in bladder cancer tissues with homozygous insertion genotype was higher than that with deletion allele.

Conclusions

In conclusion, the -94 ins/del ATTG polymorphism in NFKB1 promoter may contribute to the etiology of bladder cancer in the Chinese population.     

Multifactor Effects and Evidence of Potential Interaction between Complement Factor H Y402H and LOC387715 A69S in Age-Related Macular Degeneration

Background

Variants in the complement cascade genes and the LOC387715/HTRA1, have been widely reported to associate with age-related macular degeneration (AMD), the most common cause of visual impairment in industrialized countries.

Methods/Principal Findings

We investigated the association between the LOC387715 A69S and complement component C3 R102G risk alleles in the Finnish case-control material and found a significant association with both variants (OR 2.98, p = 3.75×10⁻⁹; non-AMD controls and OR 2.79, p = 2.78×10⁻¹⁹, blood donor controls and OR 1.83, p = 0.008; non-AMD controls and OR 1.39, p = 0.039; blood donor controls), respectively. Previously, we have shown a strong association between complement factor H (CFH) Y402H and AMD in the Finnish population. A carrier of at least one risk allele in each of the three susceptibility loci (LOC387715, C3, CFH) had an 18-fold risk of AMD when compared to a non-carrier homozygote in all three loci. A tentative gene-gene interaction between the two major AMD-associated loci, LOC387715 and CFH, was found in this study using a multiplicative (logistic regression) model, a synergy index (departure-from-additivity model) and the mutual information method (MI), suggesting that a common causative pathway may exist for these genes. Smoking (ever vs. never) exerted an extra risk for AMD, but somewhat surprisingly, only in connection with other factors such as sex and the C3 genotype. Population attributable risks (PAR) for the CFH, LOC387715 and C3 variants were 58.2%, 51.4% and 5.8%, respectively, the summary PAR for the three variants being 65.4%.

Conclusions/Significance

Evidence for gene-gene interaction between two major AMD associated loci CFH and LOC387715 was obtained using three methods, logistic regression, a synergy index and the mutual information (MI) index.     

Obesity Has an Interactive Effect with Genetic Variation in the Activating Transcription Factor 6 Gene on the Risk of Pre-Diabetes in Individuals of Chinese Han Descent

Endoplasmic reticulum (ER) stress is one of the contributing factors to the development of β-cell failure in type 2 diabetes. ER stress response through ATF6 has been shown to play an important role in insulin resistance and pancreatic β-cell function. We investigated whether genetic polymorphisms in ATF6 were associated with the risk of pre-diabetes in a Chinese Han population, and whether they had a synergistic effect with obesity. Our samples included 828 individuals who were diagnosed as pre-diabetic, and 620 controls. The minor allele A at rs2340721 was associated with increased risk for pre-diabetes(p = 0.013), and this association was still significant after adjusting for gender, age, body mass index (BMI), and waist-hip ratio(p′ = 0.011). BMI, treated as a continuous variable, and rs2340721 had an interactive effect on pre-diabetic risk(p for interaction = 0.003, β = 0.106). Carriers of GG at rs7522210 were also at a higher risk compared to non-carriers (OR = 1.390, 95%CI:1.206–1.818, p = 0.013, adjusted OR′ = 1.516, 95%CI:1.101–2.006, p′ = 0.006). GG homozygotes had increased fasting blood glucose (FBG) levels(GG vs CX: 5.6±0.52 vs 5.5±0.57 mmol/L, p = 0.016), lower insulin levels (0,30,120 minutes after glucose load) (p<0.05), and reduced areas under the insulin curve than non-carriers(GG vs CX:67.3(44.2–102.3) vs 73.1(49.4–111.4), p = 0.014). rs10918270 was associated with FBG, and rs4657103 with 2 hour glucose levels after a 75 g glucose load. We also identified a haplotype of TTAG composed of rs4657103, rs2134697, rs2340721, and rs12079579, which was associated with pre-diabetes. The genetic variation in ATF6 is associated with pre-diabetes and has interactive effects with BMI on pre-diabetes in the Chinese Han population.     

Association of Genetic Variants with Isolated Fasting Hyperglycaemia and Isolated Postprandial Hyperglycaemia in a Han Chinese Population

Background

Though multiple single nucleotide polymorphisms (SNPs) associated with type 2 diabetes have been identified, the genetic bases of isolated fasting hyperglycaemia (IFH) and isolated postprandial hyperglycaemia (IPH) were still unclear. In present study, we aimed to investigate the association of genome-wide association study-validated genetic variants and IFH or IPH in Han Chinese.

Methods/Principal Findings

We genotyped 27 validated SNPs in 6,663 unrelated individuals comprising 341 IFH, 865 IPH, 1,203 combined fasting hyperglycaemia and postprandial hyperglycaemia, and 4,254 normal glycaemic subjects of Han ancestry. The distributions of genotype frequencies of FTO, CDKAL1 and GCKR were significant different between individuals with IFH and those with IPH (SNP(p_trend): rs8050136(0.0024), rs9939609(0.0049), rs7756992(0.0122), rs780094(0.0037)). Risk allele of FTO specifically increased the risk of IFH (rs8050136: OR 1.403 [95% CI 1.125–1.750], p = 0.0027; rs9939609: 1.398 [1.120–1.744], p = 0.0030). G allele of CDKAL1 specifically increased the risk of IPH (1.217 [1.092–1.355], p = 0.0004). G allele of GCKR increased the risk of IFH (1.167 [0.999–1.362], p = 0.0513), but decreased the risk of IPH (0.891 [0.801–0.991], p = 0.0331). In addition, TCF7L2 and KCNQ1 increased the risk of both IFH and IPH. When combined, each additional risk allele associated with IFH increased the risk for IFH by 1.246-fold (p<0.0001), while each additional risk allele associated with IPH increased the risk for IPH by 1.190-fold (p<0.0001).

Conclusion/Significance

Our results indicate that genotype distributions of variants from FTO, GCKR, CDKAL1 were different between IPH and IFH in Han Chinese. Variants of genes modulating insulin sensitivity (FTO, GCKR) contributed to the risk of IFH, while variants of genes related to beta cell function (CDKAL1) increase the risk of IPH.