Familial autoimmune diseases linked to pediatric juvenile idiopathic arthritis

The risk of juvenile idiopathic arthritis (JIA) is greater among children with familial autoimmune diseases (AD), according to a recent study published in Pediatric Rheumatology.

There are 7 subtypes of arthritis under JIA, all of which appear in patients before they are aged 16 years, and last for over 6 weeks. Of these, 6 arthritis subtypes are considered ADs, with the exception being systemic JIA. 

ADs have been observed to cluster in families, sharing certain pathogenic mechanisms and genetic factors, but the association between ADs and JIA is unclear. In 1 study, 32% of patients with JIA had at least 1 first-degree relative with an AD. Family history of AD has also been associated with greater disease activity in individuals with JIA.

To understand the association between JIA in children and ADs in parents, investigators gathered and analyzed data from the international observational Pharmachild registry. Since 2011, Pharmachild has studied the safety and efficacy of drug therapies against JIA.

Patients with JIA being treated with nonsteroidal anti-inflammatory drugs were included in the registry. If family history of AD was not available, then the patient was excluded from the study.

Reported ADs in first-degree relatives were evaluated by 3 investigators and put into the following categories: psoriasis, autoimmune thyroid disease, rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, JIA, asthma, insulin-dependent diabetes mellitus, systemic lupus erythematosus, vitiligo, celiac disease, multiple sclerosis, uveitis, sarcoidosis, reactive arthritis, Sjögren’s syndrome, rheumatic fever, vasculitis, Still’s disease, familial Mediterranean fever, other autoimmune arthritis, other connective tissue diseases, and other AD.

Demographic and disease characteristics of participants were also gathered. There were 8673 patients with JIA in the final analysis, most of which were treated in European centers.

The time from disease onset until entry in the study for patients was a median 139 days. A family history of AD was seen in 1231 patients, about 90% of which had a family history of 1 AD, about 9% a history of 2 ADs, and about 1% a history of 3 or more ADs.

Enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis were seen more often in patients with a family history of AD. These patients were often also older at JIA onset.

In parents of the included JIA patients, 1366 ADs were reported, with psoriasis and ankylosing spondylitis being the most common diseases. Several other ADs were also more common in these individuals compared to a general population.

These results indicated increased risks in JIA development in children with a familial history of AD. Investigators concluded that AD history should be noted when diagnosing JIA.

Reference

van Straalen JW, de Roock S, Giancane G,Alexeeva E, Koskova E, Mesa-del-Castillo Bermejo P, et al. Prevalence of familial autoimmune diseases in juvenile idiopathic arthritis: results from the international Pharmachild registry. Pediatr Rheumatol. 2022. doi:10.1186/s12969-022-00762-y