Polymorphisms of PXK are associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in Chinese mainland population

Identification of non-HLA genes associated with development of islet autoimmunity and type 1 diabetes in the prospective TEDDY cohort

Traditional linkage analysis and genome-wide association studies have identified HLA and a number of non-HLA genes as genetic factors for islet autoimmunity (IA) and type 1 diabetes (T1D). However, the relative risk associated with previously identified non-HLA genes is usually very small as measured in cases/controls from mixed populations. Genetic associations for IA and T1D may be more accurately assessed in prospective cohorts. In this study, 5806 subjects from the TEDDY (The Environmental Determinants of Diabetes in the Young) study, an international prospective cohort study, were genotyped for 176,586 SNPs on the ImmunoChip. Cox proportional hazards analyses were performed to discover the SNPs associated with the risk for IA, T1D, or both. Three regions were associated with the risk of developing any persistent confirmed islet autoantibody: one known region near SH2B3 (HR = 1.35, p = 3.58 × 10-7) with Bonferroni-corrected significance and another known region near PTPN22 (HR = 1.46, p = 2.17 × 10-6) and one novel region near PPIL2 (HR = 2.47, p = 9.64 × 10-7) with suggestive evidence (p < 10-5). Two known regions (PTPN22: p = 2.25 × 10-6, INS; p = 1.32 × 10-7) and one novel region (PXK/PDHB: p = 8.99 × 10-6) were associated with the risk for multiple islet autoantibodies. First appearing islet autoantibodies differ with respect to association. Two regions (INS: p = 5.67 × 10-6 and TTC34/PRDM16: 6.45 × 10-6) were associated if the fist appearing autoantibody was IAA and one region (RBFOX1: p = 8.02 × 10-6) was associated if the first appearing autoantibody was GADA. The analysis of T1D identified one region already known to be associated with T1D (INS: p = 3.13 × 10-7) and three novel regions (RNASET2, PLEKHA1, and PPIL2; 5.42 × 10-6 > p > 2.31 × 10-6). These results suggest that a number of low frequency variants influence the risk of developing IA and/or T1D and these variants can be identified by large prospective cohort studies using a survival analysis approach.

Association between KIAA0319L, PXK and JAZF1 gene polymorphisms and unexplained recurrent pregnancy loss in Chinese Han couples

KIAA0319L, PXK and JAZF1 gene polymorphisms were investigated to determine whether they conferred susceptibility to unexplained recurrent pregnancy loss (URPL) in a group of Chinese Han patients. Genotyping and sequencing of the single nucleotide polymorphisms (SNP) rs2275247(A/G) in KIAA0319L, rs2176082(C/T) and rs6445975(G/T) in PXK and the rs1635852(C/T) in JAZF1 were carried out in 84 couples with URPL and 102 healthy couples with at least one live birth. Frequencies of the SNP rs2176082(C/T) in PXK gene were significantly different between women with URPL and control women: P < 0.05; OR 95% CI 0.530 (0.287 to 0.979); OR 95% CI 0.482 (0.254 to 0.911) but were not significantly different after Bonferroni correction. The frequencies of the SNP rs2176082(C/T) in PXK gene showed no difference between the husband of a woman with URPL and a control husband: OR 95% CI 1.494 (0.821 to 2.721); OR 95% CI 1.567 (0.841 to 2.921). No statistically significant differences were observed in the distribution of any genotype or allele frequency or any genetic model of the other three SNPs between couples with URPL and control couples. Therefore, the rs2176082(C/T) polymorphism of PXK might play a possible role in the development of URPL in Chinese Han women.

A systemic sclerosis and systemic lupus erythematosus pan-meta-GWAS reveals new shared susceptibility loci

Systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are two archetypal systemic autoimmune diseases which have been shown to share multiple genetic susceptibility loci. In order to gain insight into the genetic basis of these diseases, we performed a pan-meta-analysis of two genome-wide association studies (GWASs) together with a replication stage including additional SSc and SLE cohorts. This increased the sample size to a total of 21,109 (6835 cases and 14,274 controls). We selected for replication 19 SNPs from the GWAS data. We were able to validate KIAA0319L (P = 3.31 × 10(-11), OR = 1.49) as novel susceptibility loci for SSc and SLE. Furthermore, we also determined that the previously described SLE susceptibility loci PXK (P = 3.27 × 10(-11), OR = 1.20) and JAZF1 (P = 1.11 × 10(-8), OR = 1.13) are shared with SSc. Supporting these new discoveries, we observed that KIAA0319L was overexpressed in peripheral blood cells of SSc and SLE patients compared with healthy controls. With these, we add three (KIAA0319L, PXK and JAZF1) and one (KIAA0319L) new susceptibility loci for SSc and SLE, respectively, increasing significantly the knowledge of the genetic basis of autoimmunity.

Associations between PXK and TYK2 polymorphisms and systemic lupus erythematosus: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether phox homology domain containing serine/threonine kinase (PXK) and tyrosine kinase 2 (TYK2) confer susceptibility to systemic lupus erythematosus (SLE).

MATERIALS AND METHODS

The authors conducted meta-analyses on associations between SLE susceptibility and the rs6445975 polymorphism of PXK and the rs2304256, rs12720270, rs280519, and rs1272036 polymorphisms of TYK2.

RESULTS

A total of 13 separate comparisons studies were included in this meta-analysis. Meta-analysis identified an association between SLE and the 2 allele of the rs6445975 polymorphism in the overall population [odds ratio (OR) = 1.151, 95 % confidence interval (CI) = 1.086-1.291, P = 1.8E-06]. Stratification by ethnicity identified a significant association between this polymorphism and SLE in Europeans (OR = 1.198, 95 % CI = 1.118-1.285, P = 3.4E-07), but not in Asians. Meta-analysis identified a significant negative association between SLE and the 2 allele of the rs2304256 polymorphism in the overall population (OR = 0.808, 95 % CI = 0.659-0.990, P = 0.040), and a significant negative association was found in Europeans, but not in Asians.

CONCLUSIONS

This meta-analysis shows that the rs6445975 polymorphism of PXK and the rs2304256 polymorphism of TYK2 are associated with the development of SLE in Europeans.