Proteomic analyses reveal cystatin c is a promising biomarker for evaluation of systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple organ involvement, especially the kidneys. However, the underlying mechanism remains unclear, and accurate biomarkers are still lacking. This study aimed to identify biomarkers to assess organ damage and disease activity in patients with SLE using quantitative proteomics. METHODS: Proteomic analysis was performed using mass spectrometry in 15 patients with SLE and 15 age-matched healthy controls. Proteomic profiles were compared in four main subtypes: SLE with proteinuria (SLE-PN), SLE without proteinuria (SLE-non-PN), SLE with anti-dsDNA positivity (SLE-DP), and SLE with anti-dsDNA negativity (SLE-non-DP). Gene ontology biological process analysis revealed differentially expressed protein networks. Cystatin C (CysC) levels were measured in 200 patients with SLE using an immunoturbidimetric assay. Clinical and laboratory data were collected to assess their correlation with serum CysC levels. RESULTS: Proteomic analysis showed that upregulated proteins in both the SLE-PN and SLE-DP groups were mainly mapped to neutrophil activation networks. Moreover, CysC from neutrophil activation networks was upregulated in both the SLE-PN and SLE-DP groups. The associations of serum CysC level with proteinuria, anti-dsDNA positivity, lower complement C3 levels, and SLE disease activity index score in patients with SLE were further validated in a large independent cohort. CONCLUSIONS: Neutrophil activation is more prominent in SLE with proteinuria and anti-dsDNA positivity, and CysC is a promising marker for monitoring organ damage and disease activity in SLE.

Biological insights into systemic lupus erythematosus through an immune cell-specific transcriptome-wide association study.

OBJECTIVE: Genome-wide association studies (GWAS) have identified >100 risk loci for systemic lupus erythematosus (SLE), but the disease genes at most loci remain unclear, hampering translation of these genetic discoveries. We aimed to prioritise genes underlying the 110 SLE loci that were identified in the latest East Asian GWAS meta-analysis. METHODS: We built gene expression predictive models in blood B cells, CD4+ and CD8+ T cells, monocytes, natural killer cells and peripheral blood cells of 105 Japanese individuals. We performed a transcriptome-wide association study (TWAS) using data from the latest genome-wide association meta-analysis of 208 370 East Asians and searched for candidate genes using TWAS and three data-driven computational approaches. RESULTS: TWAS identified 171 genes for SLE (p<1.0×10-5); 114 (66.7%) showed significance only in a single cell type; 127 (74.3%) were in SLE GWAS loci. TWAS identified a strong association between CD83 and SLE (p<7.7×10-8). Meta-analysis of genetic associations in the existing 208 370 East Asian and additional 1498 cases and 3330 controls found a novel single-variant association at rs72836542 (OR=1.11, p=4.5×10-9) around CD83. For the 110 SLE loci, we identified 276 gene candidates, including 104 genes at recently-identified SLE novel loci. We demonstrated in vitro that putative causal variant rs61759532 exhibited an allele-specific regulatory effect on ACAP1, and that presence of the SLE risk allele decreased ACAP1 expression. CONCLUSIONS: Cell-level TWAS in six types of immune cells complemented SLE gene discovery and guided the identification of novel genetic associations. The gene findings shed biological insights into SLE genetic associations.

Meta-analysis of 208370 East Asians identifies 113 susceptibility loci for systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE), an autoimmune disorder, has been associated with nearly 100 susceptibility loci. Nevertheless, these loci only partially explain SLE heritability and their putative causal variants are rarely prioritised, which make challenging to elucidate disease biology. To detect new SLE loci and causal variants, we performed the largest genome-wide meta-analysis for SLE in East Asian populations. METHODS: We newly genotyped 10 029 SLE cases and 180 167 controls and subsequently meta-analysed them jointly with 3348 SLE cases and 14 826 controls from published studies in East Asians. We further applied a Bayesian statistical approach to localise the putative causal variants for SLE associations. RESULTS: We identified 113 genetic regions including 46 novel loci at genome-wide significance (p<5×10-8). Conditional analysis detected 233 association signals within these loci, which suggest widespread allelic heterogeneity. We detected genome-wide associations at six new missense variants. Bayesian statistical fine-mapping analysis prioritised the putative causal variants to a small set of variants (95% credible set size ≤10) for 28 association signals. We identified 110 putative causal variants with posterior probabilities ≥0.1 for 57 SLE loci, among which we prioritised 10 most likely putative causal variants (posterior probability ≥0.8). Linkage disequilibrium score regression detected genetic correlations for SLE with albumin/globulin ratio (rg=-0.242) and non-albumin protein (rg=0.238). CONCLUSION: This study reiterates the power of large-scale genome-wide meta-analysis for novel genetic discovery. These findings shed light on genetic and biological understandings of SLE.

The association of the UHRF1BP1 gene with systemic lupus erythematosus was replicated in a Han Chinese population from mainland China.

Single-nucleotide polymorphisms (SNPs) in the UHRF gene have been shown to be associated with systemic lupus erythematosus (SLE) in European and Hong Kong Chinese, but statistically significant evidence for association has not been found in a mainland Han Chinese population. Therefore, we selected SNP rs13205210 located in UHRF1BP1 as a candidate association from our previously published genome-wide association study (GWAS) data of SLE (1,047 cases and 1,205 controls from a mainland Han Chinese population) to explore the association between the UHRF1BP1 gene and SLE. We conducted a large-scale replication study in an additional independent sample of 3,509 cases and 8,246 controls from a mainland Han Chinese population. Real-time PCR was used to determine gene expression differences in peripheral blood mononuclear cells (PBMCs) from cases and controls. As a result, we replicated the association between the UHRF1BP1 gene and SLE (rs13205210, missense, Pmeta  = 2.26E-17, odds ratio = 1.41) by a meta-analysis of our previous GWAS and this replication study involving a total of 4,556 cases and 9,451 controls. The UHRF1BP1 mRNA expression level in PBMCs was significantly decreased in patients with SLE compared with that in healthy controls. SNP rs13205210 exhibited an expression quantitative trait loci effect on the UHRF1BP1 gene in PBMCs from patients. In conclusion, this study not only suggests that the UHRF1BP1 gene was associated with SLE in a mainland Han Chinese population, but also implied that it might be a common genetic factor contributing to SLE susceptibility in multiple populations.

HLA-IMPUTER: an easy to use web application for HLA imputation and association analysis using population-specific reference panels.

SUMMARY: HLA allele imputation from SNP genotypes has become increasingly useful, but its accuracy is heavily dependent on the reference panels used. HLA-IMPUTER implements HIBAG algorithm for HLA imputation with different population specific reference panels, including a new Han Chinese reference panel derived from 10 689 samples. We provide a convenient platform for researchers to impute HLA alleles and perform association analysis. AVAILABILITY AND IMPLEMENTATION: http://wyanglab.org: 3838/RefPanelWebsite/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Bach2 regulates aberrant activation of B cell in systemic lupus erythematosus and can be negatively regulated by BCR-ABL/PI3K.

OBJECTIVE: This study was aimed to explore the effect of Bach2 on B cells in systemic lupus erythematosus (SLE), as well as the underlying mechanisms. METHODS: Expression of Bach2, phosphorylated-Bach2 (p-Bach2), Akt, p-Akt and BCR-ABL (p210) in B cells isolated from SLE patients and the healthy persons were assessed by Western blot. Immunofluorescence staining was performed to assess the localization of Bach2 in B cells. Enzyme-linked immunosorbent assay (ELISA) was employed to detect IgG produced by B cells. Cell counting kit-8 (CCK-8) and Annexin-V FITC/PI double staining assay were adopted to evaluate cell proliferation and apoptosis in B cells, respectively. RESULTS: Compared to the healthy controls, Bach2, p-Akt and p210 were significantly decreased, while nuclear translocation of Bach2, IgG, CD40 and CD86 obviously up-regulated in B cells from SLE patients. Bach2 significantly inhibited the proliferation, promoted apoptosis of B cells from SLE patients, whereas BCR-ABL dramatically reversed cell changes induced by Bach2. Besides, BCR-ABL also inhibited nuclear translocation of Bach2 in B cells from SLE patients. Further, LY294002 treatment had no effect on decreased expression of Bach2 induced by BCR-ABL, but significantly eliminated BCR-ABL-induced phosphorylation of Bach2 and restored reduced nuclear translocation of Bach2 induced by BCR-ABL in B cells from SLE. CONCLUSIONS: Bach2 may play a suppressive role in B cells from SLE, and BCR-ABL may inhibit the nuclear translocation of Bach2 via serine phosphorylation through the PI3K pathway.

Increased expression of PRKCB mRNA in peripheral blood mononuclear cells from patients with systemic lupus erythematosus.

The polymorphism of PRKCB has been proven to be associated with systemic lupus erythematosus (SLE) in our previous study. We aimed to investigate the relationship between expression of PRKCB mRNA and the Disease Activity Index (SLEDAI) and manifestations of SLE. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was applied to examine the expression of PRKCB mRNA in peripheral blood mononuclear cells of 60 patients with SLE and 62 controls. The Sequenom MassArray System was used to detect genotype SNP rs16972959. The expression levels of PRKCB mRNA in SLE cases were significantly increased compared with those in healthy controls (P < 0.001). In addition, PRKCB mRNA expression levels were negatively correlated with the SLEDAI (P < 0.05, r = -0.322), with lower mRNA expression levels of PRKCB in patients found with higher SLEDAI, presence of a new rash (P < 0.01), and proteinuria (P < 0.05). No association evidence was observed between the genotype of the variant rs16972959 and PRKCB mRNA expression levels; however, SNP rs16972959 was found to be an expression quantitative trait loci for PRKCB with the SLE risk allele correlated with increased expression in naïve monocytes (PFDR  = 9.12 × 10-13 ) and stimulated monocytes (9.24 × 10-6  > PFDR  > 2.75 × 10-17 ). On the other hand, SNP rs16972959 of PRKCB was found to have suggestive significant associations with vasculitis (P = 0.00718) of SLE. These results indicated that expression of PRKCB mRNA may be correlated with the pathogenesis of SLE; however, more investigation is still needed.

Identification of ST3AGL4, MFHAS1, CSNK2A2 and CD226 as loci associated with systemic lupus erythematosus (SLE) and evaluation of SLE genetics in drug repositioning.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic component in its pathogenesis. Through genome-wide association studies (GWAS), we recently identified 10 novel loci associated with SLE and uncovered a number of suggestive loci requiring further validation. This study aimed to validate those loci in independent cohorts and evaluate the role of SLE genetics in drug repositioning. METHODS: We conducted GWAS and replication studies involving 12 280 SLE cases and 18 828 controls, and performed fine-mapping analyses to identify likely causal variants within the newly identified loci. We further scanned drug target databases to evaluate the role of SLE genetics in drug repositioning. RESULTS: We identified three novel loci that surpassed genome-wide significance, including ST3AGL4 (rs13238909, pmeta=4.40E-08), MFHAS1 (rs2428, pmeta=1.17E-08) and CSNK2A2 (rs2731783, pmeta=1.08E-09). We also confirmed the association of CD226 locus with SLE (rs763361, pmeta=2.45E-08). Fine-mapping and functional analyses indicated that the putative causal variants in CSNK2A2 locus reside in an enhancer and are associated with expression of CSNK2A2 in B-lymphocytes, suggesting a potential mechanism of association. In addition, we demonstrated that SLE risk genes were more likely to be interacting proteins with targets of approved SLE drugs (OR=2.41, p=1.50E-03) which supports the role of genetic studies to repurpose drugs approved for other diseases for the treatment of SLE. CONCLUSION: This study identified three novel loci associated with SLE and demonstrated the role of SLE GWAS findings in drug repositioning.

Exome-wide association study identifies four novel loci for systemic lupus erythematosus in Han Chinese population.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of considerable genetic predisposition. Genome-wide association studies have identified tens of common variants for SLE. However, the majority of them reside in non-coding sequences. The contributions of coding variants have not yet been systematically evaluated. METHODS: We performed a large-scale exome-wide study in 5004 SLE cases and 8179 healthy controls in a Han Chinese population using a custom exome array, and then genotyped 32 variants with suggestive evidence in an independent cohort of 13 246 samples. We further explored the regulatory effect of one novel non-coding single nucleotide polymorphism (SNP) in ex vivo experiments. RESULTS: We discovered four novel SLE gene regions (LCT, TPCN2, AHNAK2 and TNFRSF13B) encompassing three novel missense variants (XP_016859577.1:p.Asn1639Ser, XP_016859577.1:p.Val219Phe and XP_005267356.1:p.Thr4664Ala) and two non-coding variants (rs10750836 and rs4792801) with genome-wide significance (pmeta <5.00×10-8). These variants are enriched in several chromatin states of primary B cells. The novel intergenic variant rs10750836 exhibited an expression quantitative trait locus effect on the TPCN2 gene in immune cells. Clones containing this novel SNP exhibited gene promoter activity for TPCN2 (P=1.38×10-3) whose expression level was reduced significantly in patients with SLE (P<2.53×10-2) and was suggested to be further modulated by rs10750836 in CD19+ B cells (P=7.57×10-5) in ex vivo experiments. CONCLUSIONS: This study identified three novel coding variants and four new susceptibility gene regions for SLE. The results provide insights into the biological mechanism of SLE.

NFKB1 mediates Th1/Th17 activation in the pathogenesis of psoriasis.

This study was aimed to investigate whether NFKB1 participates in the pathogenesis of psoriasis by mediating Th1/Th17 cells. In this study, expression of NFKB1 was assessed in skin tissues from psoriasis patients and the healthy controls through Western blot and Immunohistochemistry. Enzyme-linked immunosorbent assay (ELISA) was used to analyze the serum levels of IFN-γ, IL-17 (IL-17A) and IL-17RA. The imiquimod-induced psoriasis mouse model was employed to examine the role of NFKB1 in psoriasis via the assessment of psoriasis area and severity index (PASI), including erythema, thickness and scales. The effects of NFKB1 on Th1/Th17 cells in were examined by flow cytometry. In vitro co-culture of Th1/Th17 cells isolated from different mice with HaCat cells was conducted to elucidate the effect of Th1/Th17 cells-mediated by NFKB1 on HaCat cells by MTT, wound healing and transwell invasion assay, respectively. The results showed that NF-κB p105/p50 expression in skin tissues was significantly increased in psoriasis (n = 21) compared to the healthy controls (n = 16), as well as levels of serum INF-γ and IL-17. Additionally, NF-κB p105/p50 expression in lesional skin tissues was much higher than that in non-lesional skin tissues of the same patients. In the psoriasis mouse model, NFKB1 overexpression significantly elevated the scores of erythema, thickness and scales. Besides, NFKB1 up-regulated the level of NF-κB p105/p50, INF-γ, T-bet, IL-17 and RORγt, as well as Th1/Th17 cells in skin tissues of psoriasis mice. Finally, in vitro assay confirmed that the activation of Th1 and Th17 mediated by NFKB1 in psoriasis promoted the proliferation, migration and invasion of keratinocytes. These findings suggest a critical role for NFKB1 in the regulation of Th1 and Th17 in psoriasis.

Meta-analysis followed by replication identifies loci in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as associated with systemic lupus erythematosus in Asians.

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic involvement and ethnic differences. Susceptibility genes identified so far only explain a small portion of the genetic heritability of SLE, suggesting that many more loci are yet to be uncovered for this disease. In this study, we performed a meta-analysis of genome-wide association studies on SLE in Chinese Han populations and followed up the findings by replication in four additional Asian cohorts with a total of 5,365 cases and 10,054 corresponding controls. We identified genetic variants in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as associated with the disease. These findings point to potential roles of cell-cycle regulation, autophagy, and DNA demethylation in SLE pathogenesis. For the region involving TET3 and that involving CDKN1B, multiple independent SNPs were identified, highlighting a phenomenon that might partially explain the missing heritability of complex diseases.

Association of the chromosome 11p13.5 variant and atopic dermatitis with a family history of atopy in the Chinese Han population.

BACKGROUND: Recent genome-wide association studies (GWAS) and a meta-analysis of GWAS for atopic dermatitis (AD) have identified some AD genetic loci in European and Japanese populations. OBJECTIVE: To investigate whether some novel susceptibility loci are associated with AD in the Chinese Han population. METHODS: We first selected eight novel susceptibility loci to replicate in 2,205 AD patients and 2,116 healthy controls using the Sequenom platform. Data were analyzed with PLINK 1.07 software. RESULTS: We found that rs12634229 (3q13.2), rs7927894 (11p13.5) and rs878860 (11p15.4) showed a slight association with AD (P = 0.012, P = 0.033, P = 0.020, respectively); rs6780220 (3p21.33) was preferentially related to AD with keratosis pilaris, but did not reach the threshold of significance after correction. The frequency of rs7927894 allele T was significantly different between AD patients with a positive and negative family history of atopy. CONCLUSION: The loci rs7927894 (11p13.5) are related to AD with a positive family history of atopy in Chinese Han population, providing novel insight into the genetic pathogenesis of AD.

Association analysis revealed one susceptibility locus for vitiligo with immune-related diseases in the Chinese Han population.

Generalized vitiligo is an autoimmune disease characterized by melanocyte loss, which results in patchy depigmentation of skin and hair, and is associated with an elevated risk of other immune-related diseases. However, there is no reported study on the associations between immune susceptibility polymorphisms and the risk of vitiligo with immune-related diseases. The aim of this study was to evaluate the potential influence of 10 single-nucleotide polymorphisms (SNPs) at 18q21.31 (rs10503019), 4p16.1 (rs11940117), 3q28 (rs1464510), 14q12 (rs2273844), 12q13.2 (rs2456973), 16q12.2 (rs3213758), 10q25.3 (rs4353229), 3q13.33 (rs59374417), and 10p15.1 (rs706779 and rs7090530) on vitiligo with immune-related diseases in the Chinese Han population. All SNPs were genotyped in 552 patients with vitiligo-associated immune-related diseases and 1656 controls using the Sequenom MassArray system. Data were analyzed with PLINK 1.07 software. The C allele of rs2456973 at 12q13.2 was observed to be significantly associated with vitiligo-associated immune-related diseases (autoimmune diseases and allergic diseases) (P = 0.0028, odds ratio (OR) = 1.27). In subphenotype analysis, the rs2456973 C allele was also significantly associated with early-onset vitiligo by comparing with controls (P = 0.0001) and in the case-only analysis (P = 0.0114). We confirmed that 12q13.2 was an important candidate locus for vitiligo with immune-related diseases (autoimmune diseases and allergic diseases) and affected disease phenotypes with early onset.

Four genetic variants interact to confer susceptibility to atopic dermatitis in Chinese Han population.

Atopic dermatitis is a chronic inflammatory skin disease and is affected by environmental and genetic factors. Gene-gene/environment interactions are strongly believed to contribute to the genetic risk of common diseases. A number of gene-environment interactions of atopic dermatitis were performed. However, there are few comprehensive investigations on the gene-gene (or genetic variants) interactions for atopic dermatitis. We explored the association model of 6 single nucleotide polymorphisms (SNPs) which were most significant (P < 10E-05) in our previous genome wide association study (GWAS) for atopic dermatitis, and search for the possible genetic variant interactions based on the previous GWAS data using Generalized Multifactor Dimensionality Reduction and Plink 1.07 in the combined sample of 4,636 cases and 13,559 controls. The most significant associated evidence was observed under dominant model for SNPs rs3126085, rs12085366, and rs7701890, recessive model for SNP rs17173197, and additive model for SNPs rs2393903 and rs6010620. Three significant pair-way interactions were observed, including PRKAG2 and FLG SNPs (rs17173197 × rs3126085, P combined = 1.11E-15), PRKAG2 and TMEM232-SLC25A46 SNPs (rs17173197 × rs7701890, P combined = 2.22E-15), PRKAG2 and TNFRSF6B-ZGPAT SNPs (rs17173197 × rs6010620, P combined = 6.66E-16). Besides, a three-way significant interaction among PRKAG2, TMEM232-SLC25A46 and TNFRSF6B-ZGPAT SNPs (rs17173197 × rs7701890 × rs6010620, P combined = 5.99E-15) was observed in this study. These four genetic variant interactions confer susceptibility to atopic dermatitis, and highlight the genetic variant interactions in the etiology of atopic dermatitis in Chinese Han population.

Impact of the leucocyte immunoglobulin-like receptor A3 (LILRA3) on susceptibility and subphenotypes of systemic lupus erythematosus and Sjögren's syndrome.

BACKGROUND: Recently, our research group identified the non-deleted (functional) leucocyte immunoglobulin-like receptor A3 (LILRA3) as a new genetic risk for rheumatoid arthritis. OBJECTIVES: To further investigate whether the functional LILRA3 is a new susceptibility factor for other autoimmune diseases-for example, systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS). METHODS: The LILRA3 deletion polymorphism and its tagging single nucleotide polymorphism rs103294 were genotyped for 1099 patients with SLE, 403 patients with pSS and 2169 healthy controls. Association analyses were performed in whole dataset or clinical/serological subsets. The impact of LILRA3 on SLE activity and LILRA3 expression was evaluated. RESULTS: The functional LILRA3 conferred high susceptibility to both SLE (p=3.51×10(-7), OR=2.03) and pSS (p=1.40×10(-3), OR=2.32). It was associated with almost all the clinical/serological features in SLE, especially with leucopenia (p=4.09×10(-7), OR=2.19) and thrombocytopenia (p=1.68×10(-5), OR=1.70). In pSS, functional LILRA3 was specifically associated with leucopenia (p=4.39×10(-4), OR=3.25), anti-Ro/SSA-positive subphenotypes (p=4.54×10(-3), OR=2.34) and anti-La/SSB-positive subphenotypes (p=0.012, OR=2.49). Functional LILRA3 conferred higher disease activity in patients with SLE (p=0.044) and higher LILRA3 expression in both SLE (p=5.57×10(-8)) and pSS (p=1.49×10(-7)) than in controls. CONCLUSIONS: Functional LILRA3 is a new susceptibility factor for SLE and pSS. It highly predisposes to certain phenotypes such as leucopenia and thrombocytopenia in SLE, and may confer increased disease activity in SLE and a higher risk of leucopenia and autoantibody-positive subphenotypes in pSS.

A comprehensive association analysis confirms ZMIZ1 to be a susceptibility gene for vitiligo in Chinese population.

BACKGROUND: ZMIZ1 has been shown to be associated with multiple autoimmune diseases and play a role in the development of melanocyte. The association of ZMIZ1 with vitiligo was also suggested, but the evidence did not reach genome-wide significance and has not been confirmed by independent studies. METHODS: A fine mapping analysis of the ZMIZ1 locus was carried out in the dataset of 1117 vitiligo patients and 3437 controls through deep imputation. Ten suggestive SNPs were then analysed in an independent validation cohort of 7458 cases and 7542 controls. SNPs within ZMIZ1 locus were functionally annotated using the ENCODE and RegulomeDB databases and published eQTL dataset of primary immune cells. RESULTS: A genome-wide significant association was discovered at rs1408944 (OR(combined)=1.18, p(combined)=1.38E-09) that locates at a DNAse hypersensitivity site and within a Myb_1 motif carried by the binding sites of six overlapping transcription factors (TFs) within the region. Gene Relationships Across Implicated Loci (GRAIL) analysis revealed biological connectivity between ZMIZ1 and previously discovered susceptibility loci for vitiligo as well as the six TFs. CONCLUSIONS: Our study has confirmed ZMIZ1 as a novel susceptibility locus for vitiligo and further suggested rs1408944 to be the putative causal variant that potentially interrupts TF binding and thus the transcriptional regulation of ZMIZ1.

Exome sequencing identifies SLC17A9 pathogenic gene in two Chinese pedigrees with disseminated superficial actinic porokeratosis.

BACKGROUND: Disseminated superficial actinic porokeratosis (DSAP) is a rare autosomal dominant genodermatosis characterised by annular lesions that has an atrophic centre and a prominent peripheral ridge distributed on sun exposed area. It exhibits high heterogeneity, and five linkage loci have been reported. The mevalonate kinase (MVK) gene located on 12q24 has been confirmed as one of the disease-causing genes. But, the pathogenesis of a large part of DSAP remains unclear so far. METHODS: The recruited with DSAP carried no MVK coding mutations. Exome sequencing was performed in two affected and one unaffected individual in Family 1. Cosegregation of the candidate variants was tested in other family members. Sanger sequencing in 33 individuals with familial DSAP and 19 sporadic DSAP individuals was performed for validating the causative gene. RESULTS: An average of 1.35×10(5) variants were generated from exome data and 133 novel NS/SS/indels were identified as being shared by two affected individuals but absent in the unaffected individual. After functional prediction, 25 possible deleterious variants were identified. In Family 1, a missense variant c.932G>A (p.Arg311Gln) in exon 10 of SLC17A9 was observed in cosegregation with the phenotype; this amino acid substitution was located in a highly conserved major facilitator superfamily (MFS) domain in multiple mammalian. One additional missense variant c.25C>T (p.Arg9Cys) in exon 2 of SLC17A9 was found in Family 2. CONCLUSIONS: The result identified SLC17A9 as another pathogenic gene for DSAP, which suggests a correlation between the aberrant vesicular nucleotide transporter and the pathogenesis of DSAP.

Association analyses identifying two common susceptibility loci shared by psoriasis and systemic lupus erythematosus in the Chinese Han population.

BACKGROUND: Genome-wide association studies (GWASs) have revealed a large number of genetic risk loci for many autoimmune diseases. One clear finding emerging from the published genetic studies of autoimmunity is that different autoimmune diseases, such as psoriasis and systemic lupus erythematosus (SLE), share susceptibility loci. Our study explores additional susceptibility loci shared by psoriasis and SLE in the Chinese Han population. METHODS: In total, 20 single nucleotide polymorphisms (SNPs) in 17 previously reported psoriasis susceptibility loci and 34 SNPs from 24 previously reported SLE susceptibility loci were investigated in our initial psoriasis and SLE GWAS dataset. Among these SNPs, we selected two SNPs (rs8016947 and rs4649203) with association values of p<5×10(-2) for both diseases in the GWAS data for further investigation in psoriasis (7260 cases and 9842 controls) and SLE (2207 cases and 9842 controls) using a Sequenom MassARRAY system. RESULTS: We found that these two SNPs (rs8016947 and rs4649203) in two loci (NFKBIA and IL28RA) were associated with psoriasis and SLE with genome-wide significance (Pcombined<5×10(-8) in psoriasis and Pcombined<5×10(-8) in SLE): rs8016947 at NFKBIA (Pcombined-psoriasis=3.90×10(-10), Pcombined-SLE=1.08×10(-13)) and rs4649203 at IL28RA (Pcombined-psoriasis=3.91×10(-12), Pcombined-SLE=9.90×10(-9)). CONCLUSIONS: These results showed that two common susceptibility loci (NFKBIA and IL28RA) are shared by psoriasis and SLE in the Chinese Han population.