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BackgroundSystemic lupus erythematosus (SLE) is a common systemic autoimmune disease with a complex genetic inheritance. Genome-wide association studies (GWAS) have significantly increased the number of significant loci associated with SLE risk. To date, however, established loci account for less than 30% of the disease heritability and additional risk variants have yet to be identified. Here we performed a GWAS followed by a meta-analysis to identify new genome-wide significant loci for SLE.MethodsWe genotyped a cohort of 907 patients with SLE (cases) and 1524 healthy controls from Spain and performed imputation using the 1000 Genomes reference data. We tested for association using logistic regression with correction for the principal components of variation. Meta-analysis of the association results was subsequently performed on 7,110,321 variants using genetic data from a large cohort of 4036 patients with SLE and 6959 controls of Northern European ancestry. Genetic association was also tested at the pathway level after removing the effect of known risk loci using PASCAL software.ResultsWe identified five new loci associated with SLE at the genome-wide level of significance (p < 5 × 10− 8): GRB2, SMYD3, ST8SIA4, LAT2 and ARHGAP27. Pathway analysis revealed several biological processes significantly associated with SLE risk: B cell receptor signaling (p = 5.28 × 10− 6), CTLA4 co-stimulation during T cell activation (p = 3.06 × 10− 5), interleukin-4 signaling (p = 3.97 × 10− 5) and cell surface interactions at the vascular wall (p = 4.63 × 10− 5).ConclusionsOur results identify five novel loci for SLE susceptibility, and biologic pathways associated via multiple low-effect-size loci.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1604-1) contains supplementary material, which is available to authorized users.

Background: Osteoporosis incidence in children is increasing due to the increased survival rate of patients suffering from chronic diseases and the increased use of drugs that can damage bones. Recent changes made to the definition of childhood osteoporosis, along with the lack of guidelines or national consensuses regarding its diagnosis and treatment, have resulted in a wide variability in the approaches used to treat this disease. For these reasons, the Osteogenesis Imperfecta and Childhood Osteoporosis Working Group of the Spanish Society of Pediatric Rheumatology has sounded the need for developing guidelines to standardize clinical practice with regard to this pathology. Methods: An expert panel comprised of 6 pediatricians and 5 rheumatologists carried out a qualitative literature review and provided recommendations based on evidence, when that was available, or on their own experience. The level of evidence was determined for each section using the Oxford Centre for Evidence-based Medicine (CEBM) system. A Delphi survey was conducted for those recommendations with an evidence level of IV or V. This survey was sent to all members of the SERPE. All recommendations that had a level of agreement higher or equal to 70% were included. Results: Fifty-one recommendations, categorized into eight sections, were obtained. Twenty-four of them presented an evidence level 4 or 5, and therefore a Delphi survey was conducted. This was submitted electronically and received a response rate of 40%. All recommendations submitted to the Delphi round obtained a level of agreement of 70% or higher and were therefore accepted. Conclusion: In summary, we present herein guidelines for the prevention, diagnosis and treatment of secondary childhood osteoporosis based on the available evidence and expert clinical experience. We believe it can serve as a useful tool that will contribute to the standardization of clinical practice for this pathology. Prophylactic measures, early diagnosis and a proper therapeutic approach are essential to improving bone health, not only in children and adolescents, but also in the adults they will become in the future.

OBJECTIVES: To investigate the incidence of COVID-19 in a cohort of adult and paediatric patients with rheumatic diseases receiving targeted biologic and synthetic disease modifying anti-rheumatic drugs (tDMARDs) and to explore the possible effect of these treatments in the clinical expression of COVID-19. METHODS: A cross-sectional study comprising of a telephone survey and electronic health records review was performed including all adult and paediatric patients with rheumatic diseases treated with tDMARDs in a large rheumatology tertiary centre in Barcelona, Spain. Demographics, disease activity, COVID-19 related symptoms and contact history data were obtained from the start of the 2020 pandemic. Cumulative incidence of confirmed cases (SARS-CoV-2 positive PCR test) was compared to the population estimates for the same city districts from a governmental COVID-19 health database. Suspected cases were defined following WHO criteria and compared to those without compatible symptoms. RESULTS: 959 patients with rheumatic diseases treated with tDMARDs were included. We identified 11 confirmed SARS-CoV-2 positive cases in the adult cohort and no confirmed positive cases in the paediatric cohort. All patients had a successful recovery and only one patient required admission in the intensive care unit. When using the same classification criteria (only COVID-19 positive cases with pneumonia), COVID-19 incidence rates of the rheumatic patient cohort were very similar to that of the general population [(0.48% (95% CI 0.09 to 8.65%)] and [0.58% (95% CI 5.62 to 5.99%)], respectively. We found significant differences in tDMARDs proportions between the suspected and non-suspected cases (p=0.002). CONCLUSION: Adult and paediatric patients with rheumatic diseases on tDMARDs do not seem to present a higher risk of COVID-19 or a more severe disease outcome when compared to general population. Our exploratory analysis suggests that the proportion of COVID-19 suspected cases differs between tDMARDs.

ObjectivePsoriatic arthritis (PsA) is a chronic inflammatory arthritis affecting up to 30% of patients with psoriasis (Ps). To date, most of the known risk loci for PsA are shared with Ps, and identifying disease-specific variation has proven very challenging. The objective of the present study was to identify genetic variation specific for PsA.MethodsWe performed a genome-wide association study in a cohort of 835 patients with PsA and 1558 controls from Spain. Genetic association was tested at the single marker level and at the pathway level. Meta-analysis was performed with a case–control cohort of 2847 individuals from North America. To confirm the specificity of the genetic associations with PsA, we tested the associated variation using a purely cutaneous psoriasis cohort (PsC, n=614) and a rheumatoid arthritis cohort (RA, n=1191). Using network and drug-repurposing analyses, we further investigated the potential of the PsA-specific associations to guide the development of new drugs in PsA.ResultsWe identified a new PsA risk single-nucleotide polymorphism at B3GNT2 locus (p=1.10e-08). At the pathway level, we found 14 genetic pathways significantly associated with PsA (pFDR<0.05). From these, the glycosaminoglycan (GAG) metabolism pathway was confirmed to be disease-specific after comparing the PsA cohort with the cohorts of patients with PsC and RA. Finally, we identified candidate drug targets in the GAG metabolism pathway as well as new PsA indications for approved drugs.ConclusionThese findings provide insights into the biological mechanisms that are specific for PsA and could contribute to develop more effective therapies.