Sarcoidosis is a systemic inflammatory disease characterized by the formation of granulomas in affected organs. Genome-wide association studies (GWASs) of this disease have been conducted only in European population. We present the first sarcoidosis GWAS in African Americans (AAs, 818 cases and 1,088 related controls) followed by replication in independent sets of AAs (455 cases and 557 controls) and European Americans (EAs, 442 cases and 2,284 controls). We evaluated >6 million SNPs either genotyped using the Illumina Omni1-Quad array or imputed from the 1000 Genomes Project data. We identified a novel sarcoidosis-associated locus, NOTCH4, that reached genome-wide significance in the combined AA samples (rs715299, PAA-meta = 6.51×10−10) and demonstrated the independence of this locus from others in the MHC region in the same sample. We replicated previous European GWAS associations within HLA-DRA, HLA-DRB5, HLA-DRB1, BTNL2, and ANXA11 in both our AA and EA datasets. We also confirmed significant associations to the previously reported HLA-C and HLA-B regions in the EA but not AA samples. We further identified suggestive associations with several other genes previously reported in lung or inflammatory diseases.
Systemic lupus erythematosus (SLE) occurs more frequently among woman than men. We undertook the present study to determine whether the male-female ratio in SLE families is different than expected by chance, and whether excess male fetal loss is found.
All SLE patients met the revised American College of Rheumatology Classification criteria, while SLE-unaffected subjects were shown not to satisfy these same criteria. Putative family relationships were confirmed by genetic testing. Pregnancy history was obtained from all subjects, including unrelated control woman. Adjusted Wald binomial confidence intervals (CI) were calculated for ratio of boys to girls in families and compared to the expected ratio of 1.06
There were 2578 subjects with SLE with 6056 siblings. Considering all subjects, we found 3201 boys and 5434 girls (ratio=0.59, of 95% CI 0.576–0.602). When considering only the SLE-unaffected siblings, there were 2919 boys and 3137 girls (ratio=0.93, 95%CI 0.92–0.94). In both cases, the ratio of males-to-females is statistically different than the known birth rate. Among SLE patients as well as among their sisters and mothers there was an excess of male fetal loss compared to the controls.
Siblings of SLE patients are more likely to be girls than expected. This finding may be in part explained by excess male fetal loss, which is found among SLE patients and their first degree relatives.
Systemic lupus erythematosus; sex ratio; fetal loss; pregnancy
Next Generation Sequencing studies generate a large quantity of genetic data in a relatively cost and time efficient manner and provide an unprecedented opportunity to identify candidate causative variants that lead to disease phenotypes. A challenge to these studies is the generation of sequencing artifacts by current technologies. To identify and characterize the properties that distinguish false positive variants from true variants, we sequenced a child and both parents (one trio) using DNA isolated from three sources (blood, buccal cells, and saliva). The trio strategy allowed us to identify variants in the proband that could not have been inherited from the parents (Mendelian errors) and would most likely indicate sequencing artifacts. Quality control measurements were examined and three measurements were found to identify the greatest number of Mendelian errors. These included read depth, genotype quality score, and alternate allele ratio. Filtering the variants on these measurements removed ~95% of the Mendelian errors while retaining 80% of the called variants. These filters were applied independently. After filtering, the concordance between identical samples isolated from different sources was 99.99% as compared to 87% before filtering. This high concordance suggests that different sources of DNA can be used in trio studies without affecting the ability to identify causative polymorphisms. To facilitate analysis of next generation sequencing data, we developed the Cincinnati Analytical Suite for Sequencing Informatics (CASSI) to store sequencing files, metadata (eg. relatedness information), file versioning, data filtering, variant annotation, and identify candidate causative polymorphisms that follow either de novo, rare recessive homozygous or compound heterozygous inheritance models. We conclude the data cleaning process improves the signal to noise ratio in terms of variants and facilitates the identification of candidate disease causative polymorphisms.
whole exome sequencing; variant filtering; next-generation sequencing; disease causative polymorphisms; Mendelian errors; Mendel errors; CASSI
To compare the performance of the American-European Consensus Group (AECG) and the newly proposed American College of Rheumatology (ACR) classification criteria for Sjögren's syndrome in a well-characterized sicca cohort, given ongoing efforts to resolve discrepancies and weaknesses in the systems.
In a multidisciplinary clinic for the evaluation of sicca, we assessed features of salivary and lacrimal gland dysfunction and autoimmunity as defined by tests of both AECG and ACR criteria in 646 participants. Global gene expression profiles were compared in a subset of 180 participants.
Application of the AECG and ACR criteria resulted in classification of 279 and 268 participants with SS, respectively. Both criteria were met by 244 participants (81%). In 26 of the 35 AECG+/ACR- participants, the minor salivary gland biopsy focal score was ≥1 (74%), while 9 had positive anti-Ro/La (26%). There were 24 AECG-/ACR+ who met ACR criteria mainly due to differences in the scoring of corneal staining. All patients with SS, regardless of classification, had similar gene expression profiles, which were distinct from the healthy controls.
The two sets of classification criteria yield concordant results in the majority of cases and gene expression profiling suggests that patients meeting either set of criteria are more similar to other SS participants than to healthy controls. Thus, there is no clear evidence for increased value of the new ACR criteria over the old AECG criteria from the clinical or biological perspective. It is our contention, supported by this report, that improvements in diagnostic acumen will require a more fundamental understanding of the pathogenic mechanisms than is at present available.
Sjögren's syndrome; Classification; Diagnosis
Common variations at the loci harboring the fat mass and obesity gene (FTO), MC4R, and TMEM18 are consistently reported as being associated with obesity and body mass index (BMI) especially in adult population. In order to confirm this effect in pediatric population five European ancestry cohorts from pediatric eMERGE-II network (CCHMC-BCH) were evaluated.
Method: Data on 5049 samples of European ancestry were obtained from the Electronic Medical Records (EMRs) of two large academic centers in five different genotyped cohorts. For all available samples, gender, age, height, and weight were collected and BMI was calculated. To account for age and sex differences in BMI, BMI z-scores were generated using 2000 Centers of Disease Control and Prevention (CDC) growth charts. A Genome-wide association study (GWAS) was performed with BMI z-score. After removing missing data and outliers based on principal components (PC) analyses, 2860 samples were used for the GWAS study. The association between each single nucleotide polymorphism (SNP) and BMI was tested using linear regression adjusting for age, gender, and PC by cohort. The effects of SNPs were modeled assuming additive, recessive, and dominant effects of the minor allele. Meta-analysis was conducted using a weighted z-score approach.
Results: The mean age of subjects was 9.8 years (range 2–19). The proportion of male subjects was 56%. In these cohorts, 14% of samples had a BMI ≥95 and 28 ≥ 85%. Meta analyses produced a signal at 16q12 genomic region with the best result of p = 1.43 × 10-7 [p(rec) = 7.34 × 10-8) for the SNP rs8050136 at the first intron of FTO gene (z = 5.26) and with no heterogeneity between cohorts (p = 0.77). Under a recessive model, another published SNP at this locus, rs1421085, generates the best result [z = 5.782, p(rec) = 8.21 × 10-9]. Imputation in this region using dense 1000-Genome and Hapmap CEU samples revealed 71 SNPs with p < 10-6, all at the first intron of FTO locus. When hetero-geneity was permitted between cohorts, signals were also obtained in other previously identified loci, including MC4R (rs12964056, p = 6.87 × 10-7, z = -4.98), cholecystokinin CCK (rs8192472, p = 1.33 × 10-6, z = -4.85), Interleukin 15 (rs2099884, p = 1.27 × 10-5, z = 4.34), low density lipoprotein receptor-related protein 1B [LRP1B (rs7583748, p = 0.00013, z = -3.81)] and near transmembrane protein 18 (TMEM18) (rs7561317, p = 0.001, z = -3.17). We also detected a novel locus at chromosome 3 at COL6A5 [best SNP = rs1542829, minor allele frequency (MAF) of 5% p = 4.35 × 10-9, z = 5.89].
Conclusion: An EMR linked cohort study demonstrates that the BMI-Z measurements can be successfully extracted and linked to genomic data with meaningful confirmatory results. We verified the high prevalence of childhood rate of overweight and obesity in our cohort (28%). In addition, our data indicate that genetic variants in the first intron of FTO, a known adult genetic risk factor for BMI, are also robustly associated with BMI in pediatric population.
BMI; obesity; polymorphism; GWAS
Immunoregulatory cytokine interleukin-10 (IL-10) is elevated in sera from patients with systemic lupus erythematosus (SLE) correlating with disease activity. The established association of IL10 with SLE and other autoimmune diseases led us to fine map causal variant(s) and to explore underlying mechanisms. We assessed 19 tag SNPs, covering the IL10 gene cluster including IL19, IL20 and IL24, for association with SLE in 15,533 case and control subjects from four ancestries. The previously reported IL10 variant, rs3024505 located at 1 kb downstream of IL10, exhibited the strongest association signal and was confirmed for association with SLE in European American (EA) (P = 2.7×10−8, OR = 1.30), but not in non-EA ancestries. SNP imputation conducted in EA dataset identified three additional SLE-associated SNPs tagged by rs3024505 (rs3122605, rs3024493 and rs3024495 located at 9.2 kb upstream, intron 3 and 4 of IL10, respectively), and SLE-risk alleles of these SNPs were dose-dependently associated with elevated levels of IL10 mRNA in PBMCs and circulating IL-10 protein in SLE patients and controls. Using nuclear extracts of peripheral blood cells from SLE patients for electrophoretic mobility shift assays, we identified specific binding of transcription factor Elk-1 to oligodeoxynucleotides containing the risk (G) allele of rs3122605, suggesting rs3122605 as the most likely causal variant regulating IL10 expression. Elk-1 is known to be activated by phosphorylation and nuclear localization to induce transcription. Of interest, phosphorylated Elk-1 (p-Elk-1) detected only in nuclear extracts of SLE PBMCs appeared to increase with disease activity. Co-expression levels of p-Elk-1 and IL-10 were elevated in SLE T, B cells and monocytes, associated with increased disease activity in SLE B cells, and were best downregulated by ERK inhibitor. Taken together, our data suggest that preferential binding of activated Elk-1 to the IL10 rs3122605-G allele upregulates IL10 expression and confers increased risk for SLE in European Americans.
Systemic lupus erythematosus (SLE), a debilitating autoimmune disease characterized by the production of pathogenic autoantibodies, has a strong genetic basis. Variants of the IL10 gene, which encodes cytokine interleukin-10 (IL-10) with known function of promoting B cell hyperactivity and autoantibody production, are associated with SLE and other autoimmune diseases, and serum IL-10 levels are elevated in SLE patients correlating with increased disease activity. In this study, to discover SLE-predisposing causal variant(s), we assessed variants within the genomic region containing IL10 and its gene family member IL19, IL20 and IL24 for association with SLE in case and control subjects from diverse ancestries. We identified SLE-associated SNP rs3122605 located at 9.2 kb upstream of IL10 as the most likely causal variant in subjects of European ancestry. The SLE-risk allele of rs3122605 was dose-dependently associated with elevated IL10 expression at both mRNA and protein levels in peripheral blood samples from SLE patients and controls, which could be explained, at least in part, by its preferential binding to Elk-1, a transcription factor activated in B cells during active disease of SLE patients. Elk-1-mediated IL-10 overexpression could be downregulated by inhibiting activation of mitogen-activated protein kinases, suggesting a potential therapeutic target for SLE.
Systemic lupus erythematosus (SLE) patients frequently have high circulating tumor necrosis factor alpha (TNF-α) levels. We explored circulating TNF-α levels in SLE families to determine whether high levels of TNF-α were clustered in a heritable pattern. We measured TNF-α in 242 SLE patients, 361 unaffected family members, 23 unaffected spouses of SLE patients, and 62 unrelated healthy controls. Familial correlations and relative recurrence risk rates for the high TNF-α trait were assessed. SLE-affected individuals had the highest TNF-α levels, and TNF-α was significantly higher in unaffected first degree relatives than healthy unrelated subjects (P = 0.0025). No Mendelian patterns were observed, but 28.4% of unaffected first degree relatives of SLE patients had high TNF-α levels, resulting in a first degree relative recurrence risk of 4.48 (P = 2.9 × 10−5). Interestingly, the median TNF-α value in spouses was similar to that of the first degree relatives. Concordance of the TNF-α trait (high versus low) in SLE patients and their spouses was strikingly high at 78.2%. These data support a role for TNF-α in SLE pathogenesis, and TNF-α levels may relate with heritable factors. The high degree of concordance in SLE patients and their spouses suggests that environmental factors may also play a role in the observed familial aggregation.
SLE disease manifestations are highly variable between patients, and the prevalence of individual clinical features differs significantly by ancestry. Serum tumor necrosis factor alpha (TNF-α) is elevated in some SLE patients, and may play a role in disease pathogenesis. We detected associations between serum TNF-α, clinical manifestations, autoantibodies, and serum IFN-α in a large multi-ancestral SLE cohort.
We studied serum TNF-α in 653 SLE patients, including 214 African-American, 298 European-Americans and 141 Hispanic-American subjects. TNF-α was measured using ELISA, and IFN-α was measured with a functional reporter cell assay. Stratified and multivariate analyses were used to detect associations in each ancestral background separately, with meta-analysis when appropriate.
Serum TNF-α levels were significantly higher in SLE patients than in nonautoimmune controls (p<5.0×10−3 for each ancestral background). High serum TNF-α was positively correlated with high serum IFN-α when tested in the same sample across all ancestral backgrounds (meta-analysis OR=1.8, p=1.2×10−3). While serum TNF-α levels alone did not differ significantly between SLE patients of different ancestral backgrounds, the proportion of patients with concurrently high TNF-α and high IFN-α was highest in African-Americans and lowest in European-Americans (p=5.0×10−3). Serum TNF-α was not associated with autoantibodies, clinical criteria for the diagnosis of SLE, or age at time of sample.
Serum TNF-α levels are high in many SLE patients, and we observed a positive correlation between serum TNF-α and IFN-α. These data support a role for TNF-α in SLE pathogenesis across all ancestral backgrounds, and suggest important cytokine subgroups within the disease.
systemic lupus erythematosus; tumor necrosis factor alpha; autoantibodies, ancestry
Systemic lupus erythematosus (SLE) is a common systemic autoimmune disease with complex etiology but strong clustering in families (λS = ~30). We performed a genome-wide association scan using 317,501 SNPs in 720 women of European ancestry with SLE and in 2,337 controls, and we genotyped consistently associated SNPs in two additional independent sample sets totaling 1,846 affected women and 1,825 controls. Aside from the expected strong association between SLE and the HLA region on chromosome 6p21 and the previously confirmed non-HLA locus IRF5 on chromosome 7q32, we found evidence of association with replication (1.1 × 10−7 < Poverall < 1.6 × 10−23; odds ratio 0.82–1.62)in four regions: 16p11.2 (ITGAM), 11p15.5 (KIAA1542), 3p14.3 (PXK) and 1q25.1 (rs10798269). We also found evidence for association (P < 1 × 10−5) at FCGR2A, PTPN22 and STAT4, regions previously associated with SLE and other autoimmune diseases, as well as at ≥9 other loci (P < 2 × 10−7). Our results show that numerous genes, some with known immune-related functions, predispose to SLE.
To investigate and refine the relationships among systemic lupus erythematosus (SLE) and related autoantibodies, interferon-α (IFN-α), and various ancestral backgrounds.
We investigated quantitatively defined genetic ancestry through principal component analysis in place of self-reported ancestry.
African ancestry was found to be associated with presence of anti-RNP antibody (p = 0.0026), and anti-RNP was correlated with high levels of IFN-α (p = 2.8 × 10−5).
Our data support a model in which African ancestry increases the likelihood of SLE-associated autoantibody formation, which subsequently results in higher levels of serum IFN-α.
SYSTEMIC LUPUS ERYTHEMATOSUS; AUTOANTIBODIES; INTERFERONS; GENETICS
About 90% of patients with systemic lupus erythematosus (SLE) are female. We hypothesize that the number of X chromosomes, not sex, is a determinate of risk of SLE. Number of X chromosomes was determined by single nucleotide typing and then confirmed by karyotype or fluorescent in situ hybridization in a large group of men with SLE. Presence of an sry gene was assessed by rtPCR. We calculated 96% confidence intervals using the Adjusted Wald method, and used Bayes’ theorem to estimate the prevalence of SLE among 47,XXY and 46,XX men. Among 316 men with SLE, 7 had 47,XXY and 1 had 46,XX. The rate of Klinefelter’s syndrome (47,XXY) was statistically different from that found in control men and from the known prevalence in the population. The 46,XX man had an sry gene, which encodes the testes determining factor, on an X chromosome as a result of an abnormal crossover during meiosis. In the case of 46,XX, 1 of 316 was statistically different from the known population prevalence of 1 in 20,000 live male births. A previously reported 46,XX man with SLE had a different molecular mechanism in which there were no common gene copy number abnormalities with our patient. Thus, men with SLE are enriched for conditions with additional X chromosomes. Especially since 46,XX men are generally normal males, except for infertility, these data suggest the number of X chromosomes, not phenotypic sex, is responsible for the sex bias of SLE.
Systemic lupus erythematosus; Klinefelter’s syndrome; male 46; XX; female bias; X chromosome
Cardiac manifestations of neonatal lupus, comprising atrioventricular conduction defects and cardiomyopathy, occur in fetuses exposed to anti-Ro/SSA antibodies, and carry substantial mortality. There is strong evidence of a genetic contribution to the risk. This study was undertaken to evaluate single-nucleotide polymorphisms (SNPs) for associations with cardiac neonatal lupus.
Children of European ancestry with cardiac neonatal lupus (n = 116) were genotyped using the Illumina 370K SNP platform and merged with 3,351 controls. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for association with cardiac neonatal lupus were determined.
The 17 most significant associations with cardiac neonatal lupus were found in the HLA region. The region near the MICB gene showed the strongest variant (rs3099844; Pdom = 4.52 × 10−10, OR 3.34 [95% CI 2.29–4.89]), followed by a missense variant within C6orf10 (rs7775397; Pdom = 1.35 × 10−9, OR 3.30), which lies between NOTCH4 and BTNL2, and several SNPs near the tumor necrosis factor α gene, including rs2857595 (Padd = 1.96 × 10−9, OR 2.37), rs2230365 (Padd = 1.00 × 10−3, OR 0.46), and rs3128982 (Padd = 6.40 × 10−6, OR 1.86). Outside the HLA region, an association was detected at 21q22, upstream of the transcription regulator ets-related isoform 1 (rs743446; P = 5.45 × 10−6, OR 2.40). HLA notwithstanding, no individual locus previously implicated in autoimmune diseases achieved genome-wide significance.
These results suggest that variation near genes related to inflammatory and apoptotic responses may promote cardiac injury initiated by passively acquired autoantibodies.
Many autoimmune diseases (ADs) share similar underlying pathology and have a tendency to cluster within families, supporting the involvement of shared susceptibility genes. To date, most of the genetic variants associated with systemic lupus erythematosus (SLE) susceptibility also show association with others ADs. ITGAM and its associated ‘predisposing’ variant (rs1143679, Arg77His), predicted to alter the tertiary structures of the ligand-binding domain of ITGAM, may play a key role for SLE pathogenesis. The aim of this study is to examine whether the ITGAM variant is also associated with other ADs. We evaluated case-control association between rs1143679 and ADs (N=18,457) including primary Sjögren’s syndrome, systemic sclerosis, multiple sclerosis, rheumatoid arthritis, juvenile idiopathic arthritis, celiac disease, and type-1 diabetes. We also performed meta-analyses using our data in addition to available published data. Although the risk allele ‘A’ is relatively more frequent among cases for each disease, it was not significantly associated with any other ADs tested in this study. However, the meta-analysis for systemic sclerosis was associated with rs1143679 (pmeta=0.008). In summary, this study explored the role of ITGAM in general autoimmunity in seven non-lupus ADs, and only found association for systemic sclerosis when our results were combined with published results. Thus ITGAM may not be a general autoimmunity gene but this variant may be specifically associated with SLE and systemic sclerosis.
ITGAM; autoimmune diseases; genetic susceptibility
The efficacy biomarker of the currently licensed anthrax vaccine (AVA) is based on quantity and neutralizing capacity of anti-Protective Antigen (anti-PA) antibodies. However, animal studies have demonstrated that antibodies to Lethal Factor (LF) can provide protection against in vivo bacterial spore challenges. Improved understanding of the fine specificities of humoral immune responses that provide optimum neutralization capacity may enhance the efficacy of future passive immune globulin preparations to treat and prevent inhalation anthrax morbidity and mortality. This study (n = 1000) was designed to identify AVA vaccinated individuals who generate neutralizing antibodies and to determine what specificities correlate with protection. The number of vaccine doses, years post vaccination, and PA titer were associated with in vitro neutralization, reinforcing previous reports. In addition, African American individuals had lower serologic neutralizing activity than European Americans, suggesting a genetic role in the generation of these neutralizing antibodies. Of the vaccinated individuals, only 69 (6.9%) had moderate levels of anti-LF IgG compared to 244 (24.4%) with low and 687 (68.7%) with extremely low levels of IgG antibodies to LF. Using overlapping decapeptide analysis, we identified six common LF antigenic regions targeted by those individuals with moderate levels of antibodies to LF and high in vitro toxin neutralizing activity. Affinity purified antibodies directed against antigenic epitopes within the PA binding and ADP-ribotransferase-like domains of LF were able to protect mice against lethal toxin challenge. Findings from these studies have important implications for vaccine design and immunotherapeutic development.
Bacillus anthracis; Anthrax; Anthrax Vaccine Adsorbed; Lethal Factor; Protective Antigen; correlate of protection
To study the effect of the innate cytokine, MIF, on the susceptibility and the severity of SLE in a multinational population of Caucasian and African-American patients.
We studied the association between two functional polymorphisms in the MIF gene: a −794 CATT5-8 microsatellite repeat (rs5844572) and a −173 G/C SNP (rs755622), with SLE in 3195 patients and controls. We also measured MIF plasma levels in relation to genotypes, clinical phenotypes, and TLR 7-stimulated MIF production in vitro.
Both Caucasians and African-Americans with the high expression, −794 CATT7/173*C haplotype had lower SLE incidence (OR 0.63 [0.53, 0.89], p=0.001 in Caucasians, and OR 0.46 [0.23, 0.95], p=0.012 in African-Americans). By contrast, among patients with established SLE, those with nephritis, serositis, and CNS involvement had reduced frequencies of low expression MIF genotypes (−794 CATT5) when compared to patients without end-organ involvement (p=0.005 for serositis, p=0.023 for nephritis, and p=0.04 for CNS involvement). Plasma MIF levels and TLR7 stimulated MIF production in vitro reflected the underlying MIF genotype of the studied groups.
These data suggest that MIF, which has both pro-inflammatory properties and macrophage and B cell survival functions, exerts a dual influence on the immunopathogenesis of SLE. High expression MIF genotypes are associated with a reduced susceptibility to SLE and may contribute to an enhanced clearance of infectious pathogens. Once SLE develops however, low expression MIF genotypes may protect from ensuing, inflammatory end-organ damage.
Homozygous C1q deficiency is an extremely rare condition and strongly associated with systemic lupus erythematosus. To assess and characterize C1q deficiency in an African-American lupus pedigree, C1q genomic region was evaluated in the lupus cases and family members.
Genomic DNA from patient was obtained and C1q A, B and C gene cluster was sequenced using next generation sequencing method. The identified mutation was further confirmed by direct Sanger sequencing method in the patient and all blood relatives. C1q levels in serum were measured using sandwich ELISA method.
In an African-American patient with lupus and C1q deficiency, we identified and confirmed a novel homozygote start codon mutation in C1qA gene that changes amino acid Methionine to Arginine at position 1. The Met1Arg mutation prevents protein translation (Met1Arg). Mutation analyses of the patient’s family members also revealed the Met1Arg homozygote mutation in her deceased brother who also had lupus with absence of total complement activity consistent with a recessive pattern of inheritance.
The identification of new mutation in C1qA gene that disrupts the start codon (ATG to AGG (Met1Arg)), has not been reported previously and it expands the knowledge and importance of the C1q gene in the pathogenesis of lupus especially in high risk African-American population.
Of nearly 38 million people in the U.S. receiving statin therapy, 0.1–0.5% experience severe or life-threatening myopathic side effects.
We performed a genome-wide association study (GWAS) in patients with severe statin myopathy versus a statin-tolerant group to identify genetic susceptibility loci.
Replication studies in independent groups of severe statin myopathy (n=190) and statintolerant controls (n=130) resulted in the identification of three SNPs, rs9342288, rs1337512 and rs3857532, in the eyes shut homolog (EYS) on chromosome 6 suggestive of an association with risk for severe statin myopathy (p=0.0003–0.0008). Analysis of EYS cDNA demonstrated that EYS gene products are complex and expressed with relative abundance in the spinal cord as well as in the retina.
Structural similarities of these EYS gene products to members of the Notch signaling pathway and to agrin suggest a possible functional role in the maintenance and regeneration of the structural integrity of skeletal muscle.
Statin; myopathy; genetic association; notch; agrin; muscle; spinal cord
Asthma is a common disease of children with a complex genetic origin. Understanding the genetic basis of asthma susceptibility will allow disease prediction and risk stratification.
We sought to identify asthma susceptibility genes in children.
A nested case-control genetic association study of children of Caucasian European ancestry from a birth cohort was conducted. Single nucleotide polymorphisms (SNPs, n=116,024) were genotyped in pools of DNA samples from cohort children with physician-diagnosed asthma (n=112) and normal controls (n=165). A genomic region containing the ATPAF1 gene was significantly associated with asthma. Additional SNPs within this region were genotyped in individual samples from the same children and in eight independent study populations consisting of Caucasian, African American, Hispanic, or other ancestries. SNPs were also genotyped or imputed in two consortia control populations. ATPAF1 expression was measured in bronchial biopsies from asthmatics and controls.
Asthma was associated with a cluster of SNPs and SNP haplotypes containing the ATPAF1 gene with two SNPs achieving significance at a genome-wide level (p=2.26×10−5 to 2.2×10−8). Asthma severity was also associated with SNPs and haplotypes in the primary population. SNP and/or gene-level associations were confirmed in the four non-Hispanic populations. Haplotype associations were confirmed in the non-Hispanic populations (p=0.045 to 0.0009). ATPAF1 total RNA expression was significantly (p<0.01) higher in bronchial biopsies from asthmatics than controls.
Genetic variation in the ATPAF1 gene predisposes children of different ancestry to asthma.
asthma; ATPAF1; children; gene; genetic; genome-wide association; purinergic; respiratory; single nucleotide polymorphism; SNP
Purpose. This study evaluates high-throughput autoantibody screening and determines associated systemic lupus erythematosus (SLE) clinical features in a large lupus cohort. Methods. Clinical and demographic information, along with serum samples, were obtained from each SLE study participant after appropriate informed consent. Serum samples were screened for 10 distinct SLE autoantibody specificities and examined for association with SLE ACR criteria and subcriteria using conditional logistic regression analysis. Results. In European-American SLE patients, autoantibodies against 52 kD Ro and RNP 68 are independently enriched in patients with lymphopenia, anti-La, and anti-ribosomal P are increased in patients with malar rash, and anti-dsDNA and anti-Sm are enriched in patients with proteinuria. In African-American SLE patients, cellular casts associate with autoantibodies against dsDNA, Sm, and Sm/nRNP. Conclusion. Using a high-throughput, bead-based method of autoantibody detection, anti-dsDNA is significantly enriched in patienets with SLE ACR renal criteria as has been previously described. However, lymphopenia is associated with several distinct autoantibody specificities. These findings offer meaningful information to allow clinicians and clinical investigators to understand which autoantibodies correlate with select SLE clinical manifestations across common racial groups using this novel methodology which is expanding in clinical use.
Vitamin D deficiency is widespread and has been associated with many chronic diseases, including autoimmune disorders. A study was undertaken to explore the impact of low vitamin D levels on autoantibody production in healthy individuals, as well as B cell hyperactivity and interferon α (IFNα) activity in patients with systemic lupus erythematosus (SLE).
Serum samples from 32 European American female patients with SLE and 32 matched controls were tested for 25-hydroxyvitamin D (25(OH)D) levels, lupus-associated autoantibodies and serum IFNα activity. Isolated peripheral blood mononuclear cells were tested for intracellular phospho-ERK 1/2 as a measure of B cell activation status.
Vitamin D deficiency (25(OH)D <20 ng/ml) was significantly more frequent among patients with SLE (n=32, 69%) and antinuclear antibody (ANA)-positive controls (n=14, 71%) compared with ANA-negative controls (n=18, 22%) (OR 7.7, 95% CI 2.0 to 29.4, p=0.003 and OR 8.8, 95% CI 1.8 to 43.6, p=0.011, respectively). Patients with high B cell activation had lower mean (SD) 25(OH)D levels than patients with low B cell activation (17.2 (5.1) vs 24.2 (3.9) ng/ml; p=0.009). Patients with vitamin D deficiency also had higher mean (SD) serum IFNα activity than patients without vitamin D deficiency (3.5 (6.6) vs 0.3 (0.3); p=0.02).
The observation that ANA-positive healthy controls are significantly more likely to be deficient in vitamin D than ANA-negative healthy controls, together with the finding that vitamin D deficiency is associated with certain immune abnormalities in SLE, suggests that vitamin D plays an important role in autoantibody production and SLE pathogenesis.
Malignant hyperthermia (MH) is a pharmacogenetic, autosomal dominantly inherited disorder of skeletal muscle triggered by volatile anesthetics and infrequently by extreme exertion and heat exposure. MH has variable penetrance with an incidence ranging from 1 in 5,000 to 1 in 50,000–100,000 anesthesias. Mutations in the ryanodine receptor gene, RYR1, are found in 50–70% of cases. We hypothesized that a portion of patients with drug-induced muscle diseases, unrelated to anesthesia, such as severe statin myopathy, have underlying genetic liability that may include RYR1 gene mutations. DNA samples were collected from 885 patients in 4 groups: severe statin myopathy (n=197), mild statin myopathy (n=163), statin-tolerant controls (n=133), and non-drug-induced myopathies of unknown etiology characterized by exercise-induced muscle pain and weakness (n=392). Samples were screened for 105 mutations and variants in 26 genes associated with 7 categories of muscle disease including 34 mutations and variants in the RYR1 gene. Disease-causing mutations or variants in RYR1 were present in 3 severe statin myopathy cases, 1 mild statin myopathy case, 8 patients with non-drug-induced myopathy, and none in controls. These results suggest that disease-causing mutations and certain variants in the RYR1 gene may contribute to underlying genetic risk for non-anesthesia-induced myopathies and should be included in genetic susceptibility screening in patients with severe statin myopathy and in patients with non-statin-induced myopathies of unknown etiology.
Malignant hyperthermia; Statin myopathy; RYR1 gene mutations; Metabolic muscle disease; Coexisting genetic risk
Autoimmune thyroid disease is common in systemic lupus erythematosus (SLE). About 20% of patients with SLE have secondary Sjögren's syndrome.
Families with more than one patient with SLE were identified. All patients met the revised classification criteria, although SLE‐unaffected relatives were confirmed not to satisfy these criteria. Diagnosis of autoimmune thyroid disease and Sjögren's syndrome was made on the basis of a review of medical records, interview and questionnaire administered to patients with SLE, and by a questionnaire administered to SLE‐unaffected subjects.
Of a total of 1138 patients with SLE, 169 had a diagnosis of Sjögren's syndrome. Of these 50 (29.6%) patients also had autoimmune thyroid disease. Of the 939 patients with SLE with no diagnosis of Sjögren's syndrome, 119 (12.7%) had autoimmune thyroid disease (χ2 = 20.1, p = 0.000009). There was no association of a diagnosis of hypertension with secondary Sjögren's syndrome (42% vss 47%). Among 2291 SLE‐unaffected relatives, 44 had diagnosed primary Sjögren's syndrome and 16 (36.3%) of these also had autoimmune thyroid disease. 265 of 2247 (11.8%) subjects had autoimmune thyroid disease but no Sjögren's syndrome (χ2 = 24.2, p<0.001).
Autoimmune thyroid disease is found in excess among patients with SLE with a diagnosis of secondary Sjögren's syndrome, as well as among their SLE‐unaffected relatives with a diagnosis of primary Sjögren's syndrome.
Bacillus anthracis remains a serious bioterrorism concern, and the currently licensed vaccine remains an incomplete solution for population protection from inhalation anthrax and has been associated with concerns regarding efficacy and safety. Thus, understanding how to generate long lasting protective immunity with reduced immunizations or providing protection through post exposure immunotherapeutics are long sought goals. Through evaluation of a large military cohort, we characterized the levels of antibodies against protective antigen and found that over half of anthrax vaccinees had low levels of in vitro toxin neutralization capacity in their sera. Using solid phase epitope mapping and confirmatory assays, we identified several neutralization-associated humoral epitopes and demonstrated that select anti-peptide responses mediated protection in vitro. Finally, passively transferred antibodies specific for select epitopes provided protection in an in vivo lethal toxin mouse model. Identification of these antigenic regions has important implications for vaccine design and the development of directed immunotherapeutics.
anthrax; vaccination; antibodies; protective antigen
Hysterectomy is one of the most common surgical procedures performed in United States, and currently, one in three women in United States has had a hysterectomy by the age of 60 years. Systemic lupus erythematosus (SLE) is a common autoimmune disease and especially targets women of childbearing age at least 10 times higher than men, which reflects the major role of female sex hormones. In this retrospective study, we evaluate the potential effects of previous hysterectomy in our lupus cohort.Data collected fromstudy subject questionnaires were obtained fromthe Lupus Family Registry and Repository (LFRR) at the OklahomaMedical Research Foundation. Hysterectomy data were available from 3389 subjects. SLE patients with a positive history of hysterectomy have been selected and compared with matched lupus patients with a negative history of hysterectomy and healthy controls. Association analyses were performed, and the P values and adjusted odds ratios (ORs) were calculated. SLE patients with a negative history of hysterectomy more likely had kidney nephritis or positive anti-dsDNA than age-matched SLE patients with a history of hysterectomy before disease onset. This effect was independent of ethnicity with an OR of 6.66 (95% CI = 3.09–14.38, P = 1.00 × 10−8) in European patients and 2.74 (95% CI = 1.43–5.25, P = 0.001) in African-Americans. SLE patients with a positive history of hysterectomy before disease onset also had a later age of disease onset (P = 0.0001) after adjustment for age and race. Our findings support the notion that the influence of female sex hormones in SLE and various clinical findings are tremendous and that surgical menopause such as this could significantly affect the outcome of disease and clinical manifestations