Familial Autoimmunity in Systemic Sclerosis — Results of a French-based Case-Control Family Study

Consensus statement on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: Localized scleroderma, systemic sclerosis and overlap syndromes

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present consensus provides an update to the 2017 European Dermatology Forum Guidelines, focusing on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, updated strategies for the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this consensus provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes.

Thyroid Disorders in Systemic Sclerosis: A Comprehensive Review

Systemic sclerosis, also referred to as scleroderma, is a chronic autoimmune disease that affects both internal organs and the skin. Systemic sclerosis predominantly affects female patients and can coexist with other disorders, including those affecting the thyroid gland. Common symptoms such as fatigue and weight changes can be attributed to either systemic sclerosis or thyroid disease. In this comprehensive review, an extensive analysis is conducted using research from 2002 to 2022, sourced from PubMed. The main focus of this exploration is to understand the intricate relationship between thyroid disorders and systemic sclerosis. We obtained these results by analyzing a number of 32285 patients included in 21 original studies. The existing evidence suggests that there is a higher incidence of elevated TSH levels and hypothyroidism in patients with systemic sclerosis, particularly in females, compared to the general population. This remains true even when comparing patients from iodine-deficient regions. Additionally, there is an increased occurrence of hyperthyroidism in the context of systemic sclerosis, which negatively impacts the prognosis of these patients. Furthermore, thyroid antibodies, predominantly anti-thyroid peroxidase (anti-TPO) antibodies, and autoimmune disorders are more commonly observed in individuals with systemic sclerosis. Although thyroid nodules are not specifically linked to the disease, when considering thyroid volume, it is observed that the thyroid gland in systemic sclerosis patients has a decreased volume, possibly due to fibrosis. Conversely, other studies have revealed that patients without autoimmune thyroid diseases (AITDs) are more likely to have a history of digital ulcers, pulmonary fibrosis detected by computed tomography scan, and a requirement for immunosuppressive medication. The majority of the studies did not establish a connection between thyroid disease in these patients and the occurrence of the limited or diffuse forms of systemic sclerosis, as well as the presence of digital ulcers, calcinosis, pulmonary arterial hypertension, scleroderma renal crisis, Raynaud phenomenon, and various other clinical manifestations.

Juvenile diabetes and systemic sclerosis: just a coincidence?

BACKGROUND

Limited joint mobility (LJM), previously known as cheiroarthropathy, refers to the presence of reduced extension at the finger joints in people with diabetes and may be associated with scleroderma-like syndromes such as diabetic sclerodactyly. While scleroderma-like syndromes and LJM have been observed in patients with long-term diabetes and associated complications, the coexistence of diabetes with Juvenile systemic sclerosis (jSSc) is rarely described.

CASE PRESENTATION

We describe the case of a 14-year-old boy with long-lasting type 1 diabetes (T1D) and suspected LJM associated with Raynaud phenomenon, sclerodactyly and tapering of the fingertips. A comprehensive work-up showed positive autoantibodies (ANA, anti-Ro-52, anti-Mi-2b), abnormal nailfold capillaroscopy with a scleroderma pattern, interstitial lung disease and cardiac involvement. The overall clinical picture was consistent with the diagnosis of jSSc.

CONCLUSIONS

LJM can be the initial sign of underlying systemic sclerosis. Nailfold capillaroscopy may help differentiate jSSc from classical LJM in pediatric patients with T1D and finger contractures or skin induration of no clear origin. This case report provides a starting point for a novel hypothesis regarding the pathogenesis of jSSc. The association between T1D and jSSc may be more than a coincidence and could suggest a relationship between glucose metabolism, fibrosis and microangiopathy.

A cross-disease meta-GWAS identifies four new susceptibility loci shared between systemic sclerosis and Crohn's disease

Genome-wide association studies (GWASs) have identified a number of genetic risk loci associated with systemic sclerosis (SSc) and Crohn’s disease (CD), some of which confer susceptibility to both diseases. In order to identify new risk loci shared between these two immune-mediated disorders, we performed a cross-disease meta-analysis including GWAS data from 5,734 SSc patients, 4,588 CD patients and 14,568 controls of European origin. We identified 4 new loci shared between SSc and CD, IL12RB2, IRF1/SLC22A5, STAT3 and an intergenic locus at 6p21.31. Pleiotropic variants within these loci showed opposite allelic effects in the two analysed diseases and all of them showed a significant effect on gene expression. In addition, an enrichment in the IL-12 family and type I interferon signaling pathways was observed among the set of SSc-CD common genetic risk loci. In conclusion, through the first cross-disease meta-analysis of SSc and CD, we identified genetic variants with pleiotropic effects on two clinically distinct immune-mediated disorders. The fact that all these pleiotropic SNPs have opposite allelic effects in SSc and CD reveals the complexity of the molecular mechanisms by which polymorphisms affect diseases.

Polyautoimmunity in rheumatological conditions

Co-occurrence of autoimmune diseases (ADs) within an individual is postulated to be a frequent phenomenon in rheumatic diseases. Similar clinical signs and symptoms, pathophysiological mechanisms, genetic factors within autoimmune diseases and aggregation of diverse ADs within families sustain the theory of shared pathogenesis of several ADs (autoimmune tautology). Polyautoimmunity (PA) is defined as the presence of more than one autoimmune disease in a single patient. When three or more autoimmune diseases coexist, this condition is called multiple autoimmune syndrome (MAS). This analysis summarizes an estimated prevalence of PA in the most common rheumatic diseases, the presumable risk factors for PA and influence of concomitant diseases on the course of disease.

European Dermatology Forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: localized scleroderma, systemic sclerosis and overlap syndromes

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this guideline provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes of systemic sclerosis with diseases of the rheumatological spectrum.

Coexistence of diabetes mellitus type 1 with diffuse systemic sclerosis - case report and literature review

Diabetic sclerodactyly is a frequently recognized skin finding that may occur in patients with diabetes mellitus but coexistence of diabetes and systemic sclerosis is rare. We describe a case of coexistence of type 1 diabetes mellitus and systemic sclerosis in 42-year-old man with the history of Raynaud’s phenomenon, progressive diffuse hardening of the skin and sclerodactyly, slowly worsening with time. The medical history included type 1 diabetes since childhood with microvascular complications. The patient presented a typical capillaroscopic scleroderma-like pattern, antinuclear antibodies and sclerotic lesions in gastrointestinal system. Summing up, our case represents the rare coexistence of autoimmune diseases like diabetes mellitus type 1 and systemic sclerosis.

Familial risk of systemic sclerosis and co-aggregation of autoimmune diseases in affected families

Background

Systemic sclerosis (SSc) is a rare and devastating disease affecting skin and internal organs. Familial aggregation of SSc and co-aggregation with other autoimmune diseases is rarely reported.

Methods

We identified 23,658,577 beneficiaries registered with the National Health Insurance database in 2010, 1891 of whom had SSc. We identified 21,009,551 parent–child relationships and 17,168,340 full sibling pairs. The familial risks of SSc and other autoimmune diseases and familial transmission were estimated.

Results

The prevalence of SSc in the general population was 0.008 %. There are 3801 individuals had at least one first-degree relative with SSc, among them 3 people had SSc which was equivalent to a prevalence of 0.08 %. The adjusted relative risk (RR) (95 % CI) for SSc was 81.21 (11.40–579.72) for siblings of SSc patients. The familial transmission (genetic plus shared environmental contribution to total phenotypic variance of SSc) was 0.72. However, 84.1 % of patients were expected to be sporadic cases. The RR (95 % CI) in first-degree relatives of SSc patients was 2.64 (1.46–4.75) for rheumatoid arthritis, 6.51 (4.05–10.46) for systemic lupus erythematosus, 2.77 (1.04–7.35) for Sjögren’s syndrome, 8.05 (2.03–31.92) for idiopathic inflammatory myositis, and 1.52 (1.15–2.01) for psoriasis.

Conclusions

The risks of SSc and other autoimmune diseases are increased in relatives of people with SSc, and family factors explain over two-thirds of the phenotypic variance of the disease. These findings may be useful in counselling families of patients with SSc and for further genetic studies.

Increased incidence of multiple sclerosis in systemic sclerosis: A nationwide cohort study

OBJECTIVE

Previous studies showed inconsistent results on the association of systemic sclerosis (SSc) with multiple sclerosis (MS), and are limited by a lack of adjustment for sex and age. The goals of this retrospective cohort study were to evaluate whether SSc is associated with increased incident MS independent of sex and age.

METHODS

We enrolled patients with SSc from Taiwan's Registry of Catastrophic Illness Database and referent subjects from the National Health Insurance Research Database. Each SSc patient was matched to at most three referent subjects by sex, age, month and year of initial diagnosis of SSc. Incidence of MS in SSc patients and corresponding 95% confidence interval (95% CI) were calculated. Cox hazard regression was used to calculate the hazard ratio (HR) of MS.

RESULTS

The study enrolled 1171 patients with SSc and 3409 referent subjects. Patients with SSc had higher incidence of MS than referent subjects (9.35 per 1000 person-years, 95% CI=6.86-11.85; 0.13 per 1000 person-years, 95% CI=0.03-0.37, respectively). Similar results also occurred in both men and women. SSc was associated with increased incidence of MS after adjusting for sex and age (HR: 69.48, 95% CI=21.69-222.54).

CONCLUSION

SSc is associated with increased incidence of MS, independent of sex and age of the patients. Multidisciplinary teams should guide the assessment, treatment, and holistic care of SSc patients to reduce its morbidity.

Familial autoimmunity and polyautoimmunity in 60 Brazilian Midwest patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology, characterized by a triad of vascular injury, autoimmunity and tissue fibrosis. It is known that a positive family history is the greatest risk factor already identified for the development of SSc in a given individual. Preliminary observation of a high prevalence of polyautoimmunity and of familial autoimmunity in SSc patients support the idea that different autoimmune phenotypes may share common susceptibility variants.

OBJECTIVES

To describe the frequency of familial autoimmunity and polyautoimmunity in 60 SSc patients in the Midwest region of Brazil, as well as to report the main autoimmune diseases observed in this association of comorbidities.

METHODS

A cross-sectional study with recruitment of 60 consecutive patients selected at the Rheumatology Department, University Hospital, Medicine School, Federal University of Mato Grosso do Sul (FMUFMS), as well as interviews of their relatives during the period from February 2013 to March 2014.

RESULTS

A frequency of 43.3% of polyautoimmunity and of 51.7% of familial autoimmunity in SSc patients was found. Patients with the presence of polyautoimmunity and familial autoimmunity presented primarily the diffuse form of SSc, but this indicator did not reach statistical significance. The autoimmune diseases most frequently observed in polyautoimmunity patients were: Hashimoto's thyroiditis (53.8%), Sjögren's syndrome (38.5%), and inflammatory myopathy (11.5%). The main autoimmune diseases observed in SSc patients' relatives were: Hashimoto's thyroiditis (32.3%), rheumatoid arthritis (22.6%), and SLE (22.6%). The presence of more than one autoimmune disease in SSc patients did not correlate with disease severity or activity.

CONCLUSIONS

From the high prevalence of coexisting autoimmune diseases found in SSc patients, we stress the importance of the concept of shared autoimmunity, in order to promote a continued vigilance and promptly diagnose other possible autoimmune disease in patients, or in their kin.

Familial autoimmunity and polyautoimmunity in 60 Brazilian Midwest patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology, characterized by a triad of vascular injury, autoimmunity and tissue fibrosis. It is known that a positive family history is the greatest risk factor already identified for the development of SSc in a given individual. Preliminary observation of a high prevalence of poliautoimmunity and of familial autoimmunity in SSc patients support the idea that different autoimmune phenotypes may share common susceptibility variants.

OBJECTIVES

To describe the frequency of familial autoimmunity and poliautoimmunity in 60 SSc patients in the Midwest region of Brazil, as well as to report the main autoimmune diseases observed in this association of comorbidities.

METHODS

A cross-sectional study with recruitment of 60 consecutive patients selected at the Rheumatology Department, University Hospital, Medicine School, Federal University of Mato Grosso do Sul (FMUFMS), as well as interviews of their relatives during the period from February 2013 to March 2014.

RESULTS

A frequency of 43.3% of poliautoimmunity and of 51.7% of familial autoimmunity in SSc patients was found. Patients with presence of poliautoimmunity and familial autoimmunity presented primarily the diffuse form of SSc, but this indicator did not reach statistical significance. The autoimmune diseases most frequently observed in poliautoimmunity patients were: Hashimoto's thyroiditis (53.8%), Sjögren's syndrome (38.5%), and inflammatory myopathy (11.5%). The main autoimmune diseases observed in SSc patients' relatives were: Hashimoto's thyroiditis (32.3%), rheumatoid arthritis (22.6%), and SLE (22.6%). The presence of more than one autoimmune disease in SSc patients did not correlate with disease severity or activity.

CONCLUSIONS

From the high prevalence of coexisting autoimmune diseases found in SSc patients, we stress the importance of the concept of shared autoimmunity, in order to promote a continued vigilance and promptly diagnose other possible autoimmune disease in patients, or in their kin.

Reduced incidence of Crohn's disease in systemic sclerosis: a nationwide population study

Background

To date, there has been no studies to evaluate the incidence of Crohn’s disease in systemic sclerosis patients. The goals of this study were to evaluate the incidence of Crohn’s disease and its relationship with sex and age in patients with systemic sclerosis.

Methods

We enrolled patients with systemic sclerosis and controls from Taiwan’s Registry of Catastrophic Illness Database and National Health Insurance Research Database. Every systemic sclerosis patient was matched to at most three controls by sex, age, month and year of initial diagnosis of systemic sclerosis. The standardized incidence ratio (SIR) of Crohn’s disease in systemic sclerosis patients, and 95 % confidence interval (95 % CI) were calculated. Cox hazard regression was used to calculate the hazard ratio (HR).

Results

The study enrolled 2,829 patients with systemic sclerosis and 8,257 controls. Male and female patients with systemic sclerosis both had lower rates of incident Crohn’s disease (SIR: 0.18, 95 % CI = 0.05–0.62; SIR: 0.10, 95 % CI = 0.05–0.21, respectively). The risk of incident Crohn’s disease in systemic sclerosis was still lower than in controls when we stratified the patients according to their ages. In Cox hazard regression, the hazard rates of Crohn’s disease were lower in systemic sclerosis patients after adjusting for genders and ages (HR: 0.12, 95 % CI = 0.06–0.21, p < 0.001).

Conclusions

Systemic sclerosis is associated with decreased incidence of, irrespective of sex and age of the patients.

Overlap between systemic sclerosis and rheumatoid arthritis: a distinct clinical entity?

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disease of the connective tissue characterized by the triad of vascular injury, autoimmunity (cellular and humoral) and tissue fibrosis. It is estimated that musculoskeletal pain is a common complaint of patients with SSc, ranging from 40 to 80%, and mainly in patients with early diffuse disease. Arthritis, clinically observed, may be a feature seen in the presentation of SSc, often leading to early diagnostic errors with rheumatoid arthritis (RA). In the course of the disease, arthritis is observed in 24-97% of patients with SSc.

OBJECTIVES

To correlate the occurrence or nonoccurrence of arthritis in patients with SSc of the Midwest region of Brazil with possible distinct clinical and laboratory manifestations observed in three groups of patients. To report the frequency of true association between systemic sclerosis and rheumatoid arthritis in patients with clinically and radiologically observed synovitis.

METHODS

Sixty-one SSc patients were subsequently assessed every 3 months within 1 year, in order to clinically observe the occurrence of synovitis and its patterns of progression. Patients were divided into 3 groups: 41 patients with SSc without arthritis, 16 SSc patients with arthritis and 4 patients with overlap of SSc and RA. All patients underwent a radiological examination of the hands at the end of the study.

RESULTS

Among all patients evaluated, we found a female predominance (98.7%), mean age of 50.94 years, white color (49.2%), limited form of the disease (47.6%), time of diagnosis between 5 and 10 years (47.6%) and duration of the disease of 8.30 years. Among all patients, 14 (22.9%) had positive rheumatoid factor (RF), while among those with positive RF, only 10 patients had arthritis during one-year follow-up. The antibody anticitrulline (anti-CCP) test was performed in 24 patients, being positive in 4 of them (16.7%), with positivity being observed only in patients with SSc/RA overlap. Comparing the clinical manifestations among the groups of patients, there was a higher incidence of gastritis and cardiac valvulopathy in patients with SSc and arthritis, but not in the others. In the group of patients with SSc/RA overlap and in patients with SSc and arthritis a significant reduction in quality of life was observed, measured by HAQ index, especially in patients with arthritis present during clinical evaluation. We found radiographic changes in 42.6% of patients with SSc. However, in patients with synovitis, radiological changes consistent with rheumatoid arthritis were found in 50% of patients.

CONCLUSIONS

While the frequency of clinical arthritis observed in patients with systemic sclerosis was 32.8%, the true overlap between of SSc and RA was 6.6% in this study. We also observed the frequency of positive anti-CCP in 20% of patients with arthritis versus no patients with SSc without arthritis.

[Overlap between systemic sclerosis and rheumatoid arthritis: a distinct clinical entity?]

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disease of the connective tissue characterized by the triad of vascular injury, autoimmunity (cellular and humoral) and tissue fibrosis. It is estimated that musculoskeletal pain is a common complaint of patients with SSc, ranging from 40 to 80%, and mainly in patients with early diffuse disease. Arthritis, clinically observed, may be a feature seen in the presentation of SSc, often leading to early diagnostic errors with rheumatoid arthritis (RA). In the course of the disease, arthritis is observed in 24 to 97% of patients with SSc.

OBJECTIVES

To correlate the occurrence or nonoccurrence of arthritis in patients with SSc of the Midwest region of Brazil with possible distinct clinical and laboratory manifestations observed in three groups of patients. To report the frequency of true association between systemic sclerosis and rheumatoid arthritis in patients with clinically and radiologically observed synovitis.

METHODS

Sixty-one SSc patients were subsequently assessed every 3 months within 1 year, in order to clinically observe the occurrence of synovitis and its patterns of progression. Patients were divided into 3 groups: 41 patients with SSc without arthritis, 16 SSc patients with arthritis and 4 patients with overlap of SSc and RA. All patients underwent a radiological examination of the hands at the end of the study.

RESULTS

Among all patients evaluated, we found a female predominance (98.7%), mean age of 50.94 years, white color (49.2%), limited form of the disease (47.6%), time of diagnosis between 5 to 10 years (47.6%) and duration of the disease of 8.30 years. Among all patients, 14 (22.9%) had positive rheumatoid factor (RF), while among those with positive RF, only 10 patients had arthritis during one-year follow-up. The antibody anticitrulline (anti-CCP) test was performed in 24 patients, being positive in 4 of them (16.7%), with positivity being observed only in patients with SSc/RA overlap. Comparing the clinical manifestations among the groups of patients, there was a higher incidence of gastritis and cardiac valvulopathy in patients with SSc and arthritis, but not in the others. In the group of patients with SSc/RA overlap and in patients with SSc and arthritis a significant reduction in quality of life was observed, measured by HAQ index, especially in patients with arthritis present during clinical evaluation. We found radiographic changes in 42.6% of patients with SSc. However, in patients with synovitis, radiological changes consistent with rheumatoid arthritis were found in 50% of patients.

CONCLUSIONS

While the frequency of clinical arthritis observed in patients with systemic sclerosis was 32.8%, the true overlap between of SSc and RA was 6.6% in this study. We also observed the frequency of positive anti-CCP in 20% of patients with arthritis versus no patients with SSc without arthritis.

Targeted therapies for systemic sclerosis

Pathogenic processes that underlie the development and progression of systemic sclerosis (SSc) are being defined in preclinical, clinical and genetic studies. Important evidence of interplay between the vasculature, connective tissue and specialized epithelial structures is emerging, and abnormalities of both the innate and adaptive immune systems have been identified. In this context, information regarding pivotal mediators, pathways or cell types that could be targets for therapeutic intervention, and that might offer potential for true disease modification, is accruing. Precedent for the regression of some aspects of the pathology has been set in clinical studies showing that potential exists to improve tissue structure and function as well as to prevent disease progression. This article reviews the concept of targeted therapies and considers potential pathways and processes that might be attenuated by therapeutic intervention in SSc. As well as improving outcomes, such approaches will undoubtedly provide information about pathogenesis. The concept of translational medicine is especially relevant in SSc, and we anticipate that the elusive goal of an effective antifibrotic treatment will emerge from one of the several clinical trials currently underway or planned in this disease. Therapeutic advances in SSc would have implications and potential beyond autoimmune rheumatic diseases.

How do autoimmune diseases cluster in families? A systematic review and meta-analysis

BACKGROUND

A primary characteristic of complex genetic diseases is that affected individuals tend to cluster in families (that is, familial aggregation). Aggregation of the same autoimmune condition, also referred to as familial autoimmune disease, has been extensively evaluated. However, aggregation of diverse autoimmune diseases, also known as familial autoimmunity, has been overlooked. Therefore, a systematic review and meta-analysis were performed aimed at gathering evidence about this topic.

METHODS

Familial autoimmunity was investigated in five major autoimmune diseases, namely, rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroid disease, multiple sclerosis and type 1 diabetes mellitus. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed. Articles were searched in Pubmed and Embase databases.

RESULTS

Out of a total of 61 articles, 44 were selected for final analysis. Familial autoimmunity was found in all the autoimmune diseases investigated. Aggregation of autoimmune thyroid disease, followed by systemic lupus erythematosus and rheumatoid arthritis, was the most encountered.

CONCLUSIONS

Familial autoimmunity is a frequently seen condition. Further study of familial autoimmunity will help to decipher the common mechanisms of autoimmunity.

Brief report: candidate gene study in systemic sclerosis identifies a rare and functional variant of the TNFAIP3 locus as a risk factor for polyautoimmunity

OBJECTIVE

Systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) share some pathophysiologic bases as evidenced by individual and familial polyautoimmunity and common susceptibility genetic factors. With regard to the latter, there has been a recent shift from the "common variant" to the "rare variant" paradigm, since rare variants of TNFAIP3 and TREX1 with large effect sizes have recently been discovered in SLE. The present study was undertaken to investigate whether rare variants of TNFAIP3 and TREX1 are also associated with SSc.

METHODS

TREX1 single-nucleotide polymorphisms (SNPs) rs3135946, rs7626978, rs3135943, and rs11797 and TNFAIP3 SNPs rs9494883, rs72063345, rs5029939, rs2230926, rs117480515, and rs7749323 were genotyped in a discovery set (985 SSc patients and 1,011 controls), and replication analysis of the most relevant results was performed in a second set (622 SSc patients and 493 controls).

RESULTS

No association between TREX1 variants and SSc was observed. For TNFAIP3, we first demonstrated that a low-frequency variant, rs117480515, tagged the recently identified TT>A SLE dinucleotide. In the discovery sample, we observed that all tested TNFAIP3 variants were in linkage disequilibrium and were associated with SSc and various SSc subsets, including the polyautoimmune phenotype. We subsequently genotyped rs117480515 in the replication sample and found it to be associated solely with the SSc polyautoimmune subset (odds ratio 3.51 [95% confidence interval 2.28-5.41], P = 8.58 × 10(-9) ) in the combined populations. Genotype-messenger RNA (mRNA) expression correlation analysis revealed that the TNFAIP3 rs117480515 risk allele was associated with decreased mRNA expression.

CONCLUSION

The present findings establish the TNFAIP3 locus as a susceptibility factor for the subset of SSc with a polyautoimmune phenotype. Our results support the implication of rare/low-frequency functional variants and the critical role of A20 in autoimmunity.