IL5RA and TNFRSF6B gene variants are associated with sporadic IgA nephropathy

Interleukin Variants Are Associated with the Development and Progression of IgA Nephropathy: A Candidate-Gene Association Study and Meta-Analysis

The interleukin-1 gene cluster encodes cytokines, which modulate mesangial cell proliferation and matrix expansion, both constituting central factors in the development and progression of immunoglobulin A nephropathy (IgAN). A candidate-gene study was performed to examine the association of polymorphisms of the interleukin-1 gene cluster with the risk of progressive IgAN. To gain deeper insights into the involvement of interleukin genes in IgAN, a meta-analysis of genetic association studies (GAS) that examine the association between interleukin variants and IgAN was conducted. Association study: The case-control study consisted of 121 unrelated Caucasians with sporadic, histologically diagnosed IgAN and of 246 age- and sex-matched healthy controls. Persistent proteinuria (>2 g/24 h) and/or impaired kidney function (serum creatinine > 1.5 mg/dL) defined progressive (n = 67) vs. non-progressive (n = 54) IgAN cases. Genotypes were assessed for two promoter-region single-nucleotide polymorphisms, C-899T (rs1800587) in IL1A and C-511T (rs16944) in IL1B, and for one penta-allelic variable-length tandem repeat polymorphism (VNTR 86 bp intron 2) in IL1RN. The association of these variants with the susceptibility of IgAN and the development of progressive IgAN (healthy status, IgAN, progressive IgAN) was tested using the generalized odds ratio (ORG) metric. Linkage disequilibrium and haplotype analysis were also performed. Meta-analysis: We included in the meta-analysis 15 studies investigating association between 14 interleukin variants harbored in eight different genes and IgAN. The ORG was used to evaluate the association between interleukin variants and IgAN using random effects models. The present case-control study revealed association of IL1B C-511T (rs16944) with the progression of IgAN (p = 0.041; ORG = 2.11 (1.09-4.07)). On haplotype analysis, significant results were derived for the haplotypes C-C-1 (p = 0.005; OR = 0.456 (0.261~0.797)) and C-T-2 (p = 0.003; OR = 4.208 (1.545-11.50)). Regarding association and meta-analysis results, variants in IL1B (rs1143627 and rs16944), IL1RN (rs928940, rs439154, and rs315951) and IL10 (rs1800871) were associated with IgAN based on either genotype or allele counts. Genetic variants and haplotypes in the IL1B, IL1RN, and IL10 genes might contribute to an increased risk for development and progression of IgAN.

The Role of Decoy Receptor DcR3 in Gastrointestinal Malignancy

Malignancies are among the leading causes of mortality worldwide. Early detection and treatment are the primary targets of clinical and translational research, and may be facilitated by the recognition of novel diagnostic and prognostic biomarkers. Decoy receptor 3 (DcR3) is a soluble receptor of the tumor necrosis factor receptor superfamily of proteins (TNFRSF), which associates with its respective TNF-like ligands, Fas-L, LIGHT, and TL1A. DcR3 has been recognised as a significant anti-apoptotic factor with prominent involvement in various inflammatory and neoplastic conditions. Increased intratumor expression of DcR3 and elevated soluble DcR3 protein content in the sera of patients has been reported for various malignancies. Recent published work has suggested that monitoring of local and systemic DcR3 may provide an attractive biomarker, mainly for defining subgroups of patients with aggressive tumor behaviour and poor prognosis. The aim of the present review is to summarize and critically present existing evidence regarding the potential clinical importance of monitoring DcR3 expression in patients with malignancies of the gastrointestinal tract, as well as liver and pancreatic cancer. We also present a detailed description of the pathophysiological basis that may underlie the involvement of DcR3 in gastrointestinal carcinogenesis. Based on these data, we comment on the potential applicability of DcR3 monitoring in the diagnosis and, most importantly, the prognostic stratification of patients.

MiRNA-495-3p Attenuates TNF-α Induced Apoptosis and Inflammation in Human Nucleus Pulposus Cells by Targeting IL5RA

Intervertebral disc degeneration (IVDD) is considered to be the fundamental cause of the occurrence and development of lumbar disc herniation (LDH). The degeneration of IVDD is mainly caused by the participation of inflammatory factors. Thus, it is of great significance to analyze the pathogenesis of IVDD, which may guide clinical prevention and treatment of LDH. Our current study aims to identify the role of miR-495-3p in LDH and to further unravel the underlying mechanisms. Results in the current study showed that TNF-α treatment markedly inhibited cell viability of HNPC, increased the IL-1β level, and decreased the mRNA level of miR-495-3p in HNPC in a time-dependent manner. Up-regulation of miR-495-3p promoted cell proliferation and inhibited inflammation and apoptosis in TNF-α-induced HNPCs. To investigate the underlying molecular mechanism through which miR-495-3p regulates TNF-α-induced inflammation and apoptosis in HNPCs, we explored the possible target gene of miR-495-3p. Bioinformatics analysis indicated that IL5RA, which is an important gene for TNF-α-induced HNPC injury, was also a target gene of miR-495-3p. A luciferase reporter assay was applied to test and verify the direct target association between miR-495-3p and IL5RA. The results discovered that down-regulation of miR-495-3p markedly reversed the anti-apoptosis and anti-inflammation of sh-IL5RA. In short, the present study evaluated the roles of miR-495-3p and IL5RA in IVDD development and progression. All the data indicated that miRNA-495-3p may play a protective role via inhibiting inflammation and apoptosis in human nucleus pulposus cells by targeting IL5RA pathway. Therefore, miRNA-495-3p may be a potential agent for LDH, and our study may provide a novel strategy in LDH treatment.

Association of Immune and Inflammatory Gene Polymorphism With the Risk of IgA Nephropathy: A Systematic Review and Meta-Analysis of 45 Studies

IgA nephropathy is the most prevalent primary glomerulonephritis worldwide, with identical immunopathological characteristics caused by multiple etiologies as well as influenced by geographical and ethnical factors. To elucidate the role of immunologic and inflammatory mechanisms in the susceptibility to IgA nephropathy, we explored single nucleotide polymorphisms of related molecules in the immune pathways. We searched the PubMed database for studies that involved all gene variants of molecules in the 20 immunologic and inflammatory pathways selected from the Kyoto Encyclopedia of Genes and Genomes database. The odds ratios with their corresponding 95% confidence intervals in six genetic models (allele model, dominant model, homozygote model, heterozygote model, overdominant model, and recessive model) were summarized using fixed or random effect models. Subgroup analysis was conducted based on different ethnicities with generalized odds ratios. Heterogeneity was evaluated using the Q and I² tests. Begg’s funnel plot and Egger’s linear regression test were used to evaluating possible publication bias among the included studies, and sensitivity analysis was used to test the stability of the overall results. A total of 45 studies met our selection criteria and eight related genetic association studies were retrieved, including 320 single-nucleotide polymorphisms from 20 candidate pathways, ranging from 2000 to 2021. A total of 28,994 healthy people versus 20,600 IgA nephropathy patients were enrolled. Upon meta-analyzed results that TGFB1 (rs1800469, rs1982073, rs1800471), IL-1B (rs1143627), IL-18 (rs1946518), and TLR1 (rs5743557) showed effect with or without ethnicity difference. And 10 variants presented stable and robust related to IgA nephropathy. This research showed that genetic variants are related to the immunologic and inflammatory effects of IgA nephropathy pathogenesis. The meta-analysis results supported the previous researches, and may help deepen the understanding of pathogenesis and explore new targets for IgA nephropathy-specific immunotherapy.

Role of prognostic biomarker decoy receptor 3 and immunomodulation in kidney diseases

Decoy receptor 3 (DcR3), also known as tumor necrosis factor receptor superfamily member 6b (TNFRSF6B), was recently identified as a novel biomarker for predicting progression of kidney diseases with potential immune modulation. The purpose of this review is to discuss the current evidence related to DcR3 in kidney diseases and to compare the differences between human and animal studies both in vivo and in vitro. High serum DcR3 predicts the occurrence of peritonitis in patients receiving chronic peritoneal dialysis and is positively correlated with inflammatory markers such as interleukin-6, high-sensitivity C-reactive protein, and adhesion molecules in patients on maintenance hemodialysis (HD). Higher serum DcR3 levels not only independently predict cardiovascular and all-cause mortality in HD patients but also identify older adults on HD at risk of protein-energy wasting in combination with a low geriatric nutritional risk index. Recently, renal tubular epithelial cells (RTECs) expressing DcR3 have also been used to predict progression of chronic kidney disease. Expression of DcR3 was correlated with a 2-fold increase in serum creatinine or failure of kidney allograft. DcR3 could protect renal myofibroblasts against Fas-induced apoptosis and subsequently lead to renal fibrosis. Locally expressed DcR3 in the RTECs may suppress the FasL-Fas-mediated apoptosis of T cells, resulting in an accumulation of allo-reactive T cells. In addition to traditional biological functions, recombinant DcR3.Fc and cytomegalovirus promoter-driven human DcR3 plasmid are able to modulate the activation and differentiation of dendritic cells and macrophages via "non-decoy" action. Both progressive IgA nephropathy and autoimmune crescentic glomerulonephritis in mice can be suppressed after hydrodynamics-based gene delivery of DcR3 plasmid. DcR3-mediated effects in vitro could be surveyed via over-expressing DcR3 or addition of recombinant DcR3.Fc, and CD68-driven DcR3 transgenic mice are suitable for investigating systemic effect in vivo. Inhibition of DcR3 expression in human may be a promising approach for pathomechanism.

Trying to understand the genetics of atopic dermatitis

Atopic dermatitis (AD) is a common and complex skin disease associated with both genetic and environmental factors. Loss-of-function mutations in the filaggrin gene, encoding a structural protein with an important role in epidermal barrier function, constitutes a well recognised susceptibility locus for AD. Further, genome-wide association studies (GWAS), including large meta-analyses, have discovered 38 additional susceptibility loci with genome-wide significance. However, the reported variations only explain a fraction of the overall heritability of AD. Here, we summarize the current knowledge of the role of filaggrin and the epidermal differentiation complex as well as the results of GWAS, with an emphasis on novel findings and observations made in the past two years. Additionally, we present first results of exome sequencing for AD and discuss novel therapeutic strategies.

DcR3 gene polymorphisms are associated with sporadic breast infiltrating ductal carcinoma in Northeast Chinese women

Decoy Receptor 3 (DcR3), also called TNFRSF6β, is a member of the tumor necrosis factor receptor superfamily and is a soluble receptor for FasL. DcR3 is overexpressed in cancers and contributes to tumorigenesis through immune suppression and promotion of angiogenesis. We found that DcR3 is overexpressed in breast infiltrating ductal carcinoma (IDC) cells as compared with normal controls. We also conducted a case-control study analyzing associations of DcR3 polymorphisms with breast IDC risk. Subjects included 531 females with breast IDC and 592 age-matched healthy controls. Four DcR3 single nucleotide polymorphism loci with minor frequencies of more than 5% (rs3208008, rs41309931, rs2297441 and rs1291207) were genotyped using polymerase chain reaction restriction fragment length polymorphism and sequencing. Our results revealed significant differences in rs41309931genotypes and alleles (P < 0.01). Based on Haploview software analysis, the haplotype block A_rs3208008 G_rs41309931 G_rs2297441 A_rs1291207 exhibited the highest frequency, but, haplotype blocks A_rs3208008 T_rs41309931 G_rs2297441 A_rs1291207 and C_rs3208008 G_rs41309931 G_rs2297441 A_rs1291207 were associated with breast IDC risk. This study also detected associations between DcR3 gene polymorphisms and the clinicopathological features of breast IDC, including lymph node metastasis and C-erbB2, P53, estrogen receptor and progesterone receptor status. These data indicate that DcR3 gene polymorphisms are associated with sporadic breast IDC risk in Northeast Chinese females.

New insights into the pathogenesis of IgA nephropathy

IgA nephropathy (IgAN) is the most common diagnosis amongst primary glomerular diseases in most countries where renal biopsies are regularly performed. Only a fraction of these patients is at high risk of losing glomerular filtration rate (GFR) in particular those with high grade proteinuria, uncontrolled hypertension or already impaired GFR at diagnosis, and those with renal scars in the renal biopsy. Genetic modifiers of IgAN onset and/or course are emerging. Spontaneous animal models of IgAN are problematic given considerable species differences between the rodent and human IgA system. However, new transgenic models help to better understand the pathogenesis. A key pathogenetic role appears to be played by underglycated IgA1 as well as autoantibodies to these IgA glycoforms and IgA receptors such as CD89 and transferrin receptor 1. Once IgA and/or IgA-containing immune complexes are deposited or formed in the mesangium, secondary effector mechanisms become important including complement activation, release of mesangial growth factors (in particular platelet-derived growth factor), and finally non-IgAN-specific events that culminate in glomerular and subsequently renal tubulointerstitial scaring. Here, we review these processes and describe potential novel therapeutic targets in IgAN.

Genome-wide association study identifies TNFSF13 as a susceptibility gene for IgA in a South Chinese population in smokers

IgA is an important factor in our immune system. There are many diseases associated with it, such as IgA nephropathy, IgA deficiency, and so on. In order to describe the relationship between the genes and the IgA level, we performed a genome-wide association study of serum IgA with 1,999 healthy Chinese men in the first stage and replicated on an independent Chinese sample with 1,496 subjects in the second stage. Association between each SNP with IgA was estimated by multivariate linear regression analysis conditioned on age and smoke. Haplotype analysis for the block around the top SNP was performed. In the first stage, one genomic locus was identified to be significantly associated with IgA. The loci is TNFSF13 (17p13.1; rs3803800; P = 6.26 × 10(-8)). In smoke-specific analysis, rs3803800 was approximately significantly associated with IgA levels in smokers (P = 3.96 × 10(-7)), while no association was observed in nonsmokers (P = 2.28 × 10(-1)). In addition, we performed the haplotype analysis on chromosome 17 with the SNPs around rs3803800. Although the total P value for the haplotype did not acquire significant difference, three haplotypes (TGAG, CACG, and CACA) reached significant (P < 0.05). In conclusion, TNFSF13 could be a susceptible gene which was discovered having relationship with serum IgA level, and smoke might be a factor infecting the IgA level.

The genetic variants at the HLA-DRB1 gene are associated with primary IgA nephropathy in Han Chinese

Background

Immunoglobulin A nephropathy (IgAN), an immune-complex-mediated glomerulonephritis defined immunohistologically by the presence of glomerular IgA deposits, is the most common primary glomerular disease worldwide and a significant cause of end-stage renal disease. Familial clustering of patients with IgAN suggests a genetic predisposition.

Methods

In this study, 192 patients with IgAN and 192 normal controls in the Sichuan cohort and 935 patients with IgAN and 2,103 normal controls in the Beijing cohort were investigated. HLA-DRB1*01–DRB1*10 specificities were genotyped by the PCR–SSP technique in both cohorts. Based on the HLA-DRB1*04-positive results, the subtypes of HLA-DRB1*04 were analyzed using sequencing-based typing (SBT) in 291 IgAN cases and 420 matched controls.

Results

The frequency of HLA-DRB1*04 in the IgAN group was significantly higher than that in the control group (0.129 vs. 0.092, P = 8.29 × 10^-5, odds ratio (OR) =1.381, 95% confidence interval (CI) 1.178–1.619). Other alleles at the HLA-DRB1 locus were observed with no significant differences between the case and control groups. The dominant alleles of the HLA-DRB1*04 subtypes were DRB1*0405 in both cohorts. The frequencies of HLA-DRB1*0405 and 0403 were significantly increased in the patients compared to healthy subjects.

Conclusion

HLA-DRB1*04 was significantly associated with primary IgAN in Chinese population. This result implies that HLA-DRB1 gene plays a major role in primary IgAN.

Search for genetic association between IgA nephropathy and candidate genes selected by function or by gene mapping at loci IGAN2 and IGAN3

BACKGROUND

IgA nephropathy (IgAN) is not generally considered a hereditary disease, even though extensive evidence suggests an undefined genetic influence. Linkage analysis identified a number of genome regions that could contain variations linked to IgAN.

METHODS

In this case-control association study, genes possibly involved in the development of IgAN were investigated. DNA samples from 460 North Italian patients with IgAN and 444 controls were collected. Candidate genes were selected based on their possible functional involvement (6 genes) or because of their location within linkage-identified genomic regions IGAN2 and IGAN3 (5 and 13 genes within chromosome 4q26-31 and 17q12-22, respectively). One hundred and ninety-two tag and functional single-nucleotide polymorphisms (SNPs) were typed with Veracode GoldenGate technology (Illumina).

RESULTS

C1GALT1 showed an association with IgAN (rs1008898: P = 0.0019 and rs7790522: P = 0.0049). Associations were found when the population was stratified by gender (C1GALT1, CD300LG, GRN, ITGA2B, ITGB3 in males and C1GALT1, TRPC3, B4GALNT2 in females) and by age (TLR4, ITGB3 in patients aged <27 years). Furthermore, rs7873784 in TLR4 showed an association with proteinuria (G allele: P = 0.0091; GG genotype: P = 0.0077).

CONCLUSIONS

Age and gender are likely to evidence distinct immunological and inflammatory reactions leading to individual susceptibility to IgAN. Overall, a genetic predisposition to sporadic IgAN was found. We might hypothesize that C1GALT1 and TLR4 polymorphisms influence the risk to develop IgAN and proteinuria, respectively.

Mice overexpressing BAFF develop a commensal flora-dependent, IgA-associated nephropathy

B cell activation factor of the TNF family (BAFF) is a potent B cell survival factor. BAFF overexpressing transgenic mice (BAFF-Tg mice) exhibit features of autoimmune disease, including B cell hyperplasia and hypergammaglobulinemia, and develop fatal nephritis with age. However, basal serum IgA levels are also elevated, suggesting that the pathology in these mice may be more complex than initially appreciated. Consistent with this, we demonstrate here that BAFF-Tg mice have mesangial deposits of IgA along with high circulating levels of polymeric IgA that is aberrantly glycosylated. Renal disease in BAFF-Tg mice was associated with IgA, because serum IgA was highly elevated in nephritic mice and BAFF-Tg mice with genetic deletion of IgA exhibited less renal pathology. The presence of commensal flora was essential for the elevated serum IgA phenotype, and, unexpectedly, commensal bacteria-reactive IgA antibodies were found in the blood. These data illustrate how excess B cell survival signaling perturbs the normal balance with the microbiota, leading to a breach in the normal mucosal-peripheral compartmentalization. Such breaches may predispose the nonmucosal system to certain immune diseases. Indeed, we found that a subset of patients with IgA nephropathy had elevated serum levels of a proliferation inducing ligand (APRIL), a cytokine related to BAFF. These parallels between BAFF-Tg mice and human IgA nephropathy may provide a new framework to explore connections between mucosal environments and renal pathology.

Single nucleotidic polymorphism 844 A->G of FCAR is not associated with IgA nephropathy in Caucasians

BACKGROUND

IgA nephropathy is characterized by a high heterogeneity of clinical expression with 10-30% of patients progressing to end-stage renal failure. The gene of the FcαRI or CD89 presents a single-nucleotide polymorphism responsible for a proinflammatory phenotype of neutrophils in vitro and ex vivo. The aim of our study was to assess whether this CD89 polymorphism 844 A->G is (i) a marker of disease susceptibility and/or (ii) associated with a more severe prognosis.

METHODS

All patients diagnosed with IgA nephropathy and for whom DNA frozen sample was available were included in this European monocentric retrospective analysis and compared to a cohort of healthy volunteers. Allelic discrimination was performed by real-time quantitative polymerase chain reaction (Applied Biosystems™). We first compared the distribution of A and G alleles between patients and volunteers and then studied the relationships between alleles and renal survival, histological score, proteinuria and renal function at diagnosis.

RESULTS

Seven hundred and twenty-six patients were analyzed for the study of susceptibility and 425 in the association study. The presence of the G allele was not associated with the occurrence of IgA nephropathy (χ(2) test 0.57, ns). Likewise, renal survival and the criteria for disease activity at time of diagnosis were not affected by the presence of the G allele.

CONCLUSIONS

No significant association between 844 A->G CD89 polymorphism and the expression of the IgA nephropathy in Caucasians exists. This result does, however, not preclude the implication of other CD89 polymorphisms neither the possibility for a role of CD89 in the pathogenesis of IgA nephropathy.

A candidate gene approach to genetic contributors to the development of IgA nephropathy

BACKGROUND

Genetic factors contributing to the development of IgA nephropathy remain to be elucidated.

METHODS

The present multicenter cross-sectional case-control study measured genotype frequencies of 65 atherosclerotic disease-related gene polymorphisms in 230 Japanese patients with IgA nephropathy and 262 apparently healthy volunteers with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m(2) and negative or trace proteinuria and hematuria by dipstick test [non-chronic kidney disease (CKD) participants]. Clinical characteristics at kidney biopsy of patients with IgA nephropathy and those at the study recruitment of non-CKD participants were included as covariates in multivariate logistic regression models.

RESULTS

Among 31 gene polymorphisms with ≥5% of minor genotype in non-CKD participants, methionine synthase MTR A2756G (D919G) was significantly associated with IgA nephropathy using χ(2) test even after controlling for family-wise error rate by the method of Bonferroni (P = 0.044). A multivariate nonconditional logistic regression model identified MTR A2756G as a significant contributor of IgA nephropathy [2756AG and GG versus AA, odds ratio 0.42 (95% confidence interval 0.25-0.69) and 0.21 (95% confidence interval 0.06-0.68), P(trend) < 0.001]. After each patient with IgA nephropathy was randomly matched to a non-CKD participant on age (±5 years), gender, mean arterial pressure (±5 mmHg) and eGFR (±5 mL/min/1.73 m(2)), a multivariate conditional logistic regression model also verified their significant association [odds ratio 0.42 (95% confidence interval 0.18-1.00) and odds ratio 0.09 (95% confidence interval 0.01-0.73), P(trend) = 0.004]. MTR A2756G was not associated with slope of eGFR (mL/min/1.73 m(2)/year) in 230 patients with IgA nephropathy.

CONCLUSION

MTR A2756G was associated with the development, but not progression, of IgA nephropathy.

HLA has strongest association with IgA nephropathy in genome-wide analysis

Demographic and family studies support the existence of a genetic contribution to the pathogenesis of IgA nephropathy, but results from genetic association studies of candidate genes are inconsistent. To systematically survey common genetic variation in this disease, we performed a genome-wide analysis in a cohort of patients with IgA nephropathy selected from the UK Glomerulonephritis DNA Bank. We used two groups of controls: parents of affected individuals and previously genotyped, unaffected, ancestry-matched individuals from the 1958 British Birth Cohort and the UK Blood Service. We genotyped 914 affected or family controls for 318,127 single nucleotide polymorphisms (SNPs). Filtering for low genotype call rates and inferred non-European ancestry left 533 genotyped individuals (187 affected children) for the family-based association analysis and 244 cases and 4980 controls for the case-control analysis. A total of 286,200 SNPs with call rates >95% were available for analysis. Genome-wide analysis showed a strong signal of association on chromosome 6p in the region of the MHC (P = 1 × 10(-9)). The two most strongly associated SNPs showed consistent association in both family-based and case-control analyses. HLA imputation analysis showed that the strongest association signal arose from a combination of DQ loci with some support for an independent HLA-B signal. These results suggest that the HLA region contains the strongest common susceptibility alleles that predispose to IgA nephropathy in the European population.

Polymorphisms of decoy receptor 3 are associated with risk of esophageal squamous cell carcinoma in Chinese Han

Decoy receptor 3 (DcR3) is a soluble receptor without transmembrane and intracellular sequences in its peptide. It can bind to and inactivate the apoptosis-inducing ligand FasL, LIGHT, and TL1A. The aims of this study are to genotype the two polymorphisms in the promotor of DcR3 in esophageal squamous cell cancer patients and controls and analyze the association between individual genetic variation and susceptibility to esophageal squamous cell carcinoma (ESCC). A total of 444 Chinese ESCC patients and 468 matched cancer-free controls were evaluated for the two single nucleotide polymorphisms (SNPs) in DCR3. Polymorphisms were genotyped using the SNPShot technique. The expression of DCR3 in cancer tissues was detected by reverse transcription-polymerase chain reaction. There were significant differences in the allele's distribution of the two SNPs among ESCC cases and controls (P < 0.01). Compared with the 147TT genotype, the 147CC genotype was associated with significant elevated risk of ESCC (odds ratio, 1.89; 95% confidence interval, 1.30-2.96). The risk of 147CC genotype was more notable (odds ratio, 2.19; 95% confidence interval, 1.32-3.64) in the smokers than in the nonsmokers (odds ratio, 1.25; 95% confidence interval, 0.59-2.69). In the stratification analyses, we also found there was a strong correlation between 147 CC and the clinical TNM stage (P < 0.01). Furthermore, significant difference in DCR3 expression in ESCC tissues was found between subgroups with different 147C/T variant. Our finding suggested that DcR3 promoter polymorphism 147C/T might influence the susceptibility to ESCC in the Chinese Han population, maybe by influencing DcR3 expression.

Unravelling the genetic basis of renal diseases; from single gene to multifactorial disorders

Chronic kidney disease is common with up to 5% of the adult population reported to have an estimated glomerular filtration rate of < 60 ml/min/1.73 m(2). A large number of pathogenic mutations have been identified that are responsible for 'single gene' renal disorders, such as autosomal dominant polycystic kidney disease and X-linked Alport syndrome. These single gene disorders account for < 15% of the burden of end-stage renal disease that requires dialysis or kidney transplantation. It has proved more difficult to identify the genetic susceptibility underlying common, complex, multifactorial kidney conditions, such as diabetic nephropathy and hypertensive nephrosclerosis. This review describes success to date and explores strategies currently employed in defining the genetic basis for a number of renal disorders. The complementary use of linkage studies, candidate gene and genome-wide association analyses are described and a collation of renal genetic resources highlighted.

Interleukin-1 cluster gene polymorphisms in childhood IgA nephropathy

We have carried out a study with the aim of investigating the association between single nucleotide polymorphisms (SNPs) of the IL-1 gene cluster and childhood IgA nephropathy (IgAN). SNPs of the IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist (RN) genes (IL1A, IL1B, and IL1RN, respectively) were analyzed in 182 patients with childhood IgAN and in 500 healthy controls. The IgAN patients were also dichotomized and compared with respect to proteinuria (<4 mg and >or=4 mg/m(2) per hour, respectively), the presence or absence of podocyte foot process effacement, and the presence of pathologically early and advanced disease markers, such as interstitial fibrosis, tubular atrophy, or global sclerosis. Significant differences in SNP frequencies were observed for the IL1B and IL1RN genes (rs1143627, rs3917356, and rs1143633 in the IL1B gene, and rs928940, rs439154, and rs315951 in the IL1RN gene). Moreover, rs1143627, rs3917356, and rs1143633 of IL1B were found to be significantly associated with the presence of podocyte foot process effacement. Our results suggest that the IL1B and IL1RN genes are associated with increased susceptibility to IgAN in children. They also suggest that the development of proteinuria in IgAN is related to IL1A and that podocyte foot process effacement is associated with IL1B.

Is complement factor H a susceptibility factor for IgA nephropathy?

There is substantial evidence to suggest that complement activation plays a pivotal role in the pathogenesis of IgA nephropathy. Mesangial C3 deposition is seen in approximately 90% of patients and polymeric IgA has been shown to activate the alternative and lectin pathways. In addition there have been reports of deficiency and mutations in the serum complement regulator factor H (CFH) in association with IgA nephropathy. In this study we have examined the hypothesis that CFH is a susceptibility factor for IgA nephropathy. In 46 IgA nephropathy patients we undertook genotyping of three CFH SNPS (rs3753394, rs3753396 and rs1065489). There was no significant difference in the allele frequency of these 3 SNPs between the patients and normal controls. In the same group of patients we undertook mutation screening of CFH exons 18-23 using direct sequencing and found no abnormalities. All the patients had a normal serum factor H concentration. In this small cohort of IgA nephropathy patients we have not found evidence to support the hypothesis that factor H is a major susceptibility factor for the disease.