[Pubmed] Familial autoimmunity in patients with idiopathic inflammatory myopathies

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J Intern Med. 2022 Sep 27. doi: 10.1111/joim.13573. Online ahead of print.

ABSTRACT

BACKGROUND: Familial associations can be indicators of shared genetic susceptibility between two diseases. Previous data on familial autoimmunity in patients with idiopathic inflammatory myopathies (IIM) are scarce and inconsistent.

OBJECTIVES: To investigate which autoimmune diseases (ADs) may share genetic susceptibility with IIM, we examined the familial associations between IIM and different ADs.

METHODS: In this Swedish population-based family study, we assembled 7615 first-degree relatives (FDRs) of 1620 patients with IIM and 37309 relatives of 7797 matched individuals without IIM. Via register linkages, we ascertained rheumatoid arthritis (RA), other rheumatic inflammatory diseases (RIDs), multiple sclerosis (MS), inflammatory bowel diseases (IBD), type 1 diabetes mellitus (T1DM), autoimmune thyroid diseases (AITD), celiac disease (CeD) and myasthenia gravis (MG) among the FDRs. We estimated familial association between IIM and each AD using conditional logistic regression and performed subgroup analyses by kinship.

RESULTS: Patients with IIM had significantly higher odds of having ≥1 FDR affected by other RIDs (adjusted odds ratio, aOR = 1.40 95% CI 1.11-1.78) and greater odds of having ≥2 FDRs affected by CeD (aOR = 3.57 95%CI 1.28-9.92) compared to the individuals without IIM. In the analyses of any FDR pairs, we observed familial associations for other RIDs (aOR = 1.34 95% CI 1.14-1.56), IBD (aOR = 1.20 95% CI 1.02-1.41), AITD (aOR = 1.10 95% CI 1.02-1.19) and CeD (aOR = 1.37 95% CI 1.08-1.74) while associations for other ADs were not statistically significant.

CONCLUSION: The observed familial associations may suggest that IIM shares genetic susceptibility with various ADs, information that may be useful for clinical counselling and guiding future genetic studies of IIM. This article is protected by copyright. All rights reserved.

PMID:36165332 | DOI:10.1111/joim.13573


Source: https://pubmed.ncbi.nlm.nih.gov/3616533 ... 2&v=2.17.8