The prevalence of arthritis in children with Down syndrome may be 2 to 3 times greater than previously reported, according to study data presented at the 2019 American College of Rheumatology/Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, held November 8 to 13, 2019, in Atlanta, Georgia.
Investigators screened children (aged 0-21 years) with Down syndrome at a regional screening clinic, where a detailed musculoskeletal examination was performed by a pediatric rheumatology clinical fellow. Suspected cases of arthropathy of Down syndrome (A-DS) were confirmed by a second physician at an affiliated clinic. Children with arthropathy received treatment according to existing guidelines for juvenile idiopathic arthritis (JIA). Data from a convenience sample of 21 children newly diagnosed with JIA were collected and compared with the Down syndrome cohort.
Over 18 months, 503 children with Down syndrome were screened for arthritis, among whom 18 were newly diagnosed with A-DS. The total number of A-DS cases was 33, including children with a diagnosis prior to screening. Based on these results, prevalence of A-DS was indicated to be 20 in 1000. Significant delay in A-DS diagnosis was observed.
The majority of A-DS cases presented with polyarticular rheumatoid factor negative arthritis, with small joints of the hands and wrists predominantly affected. No children with A-DS were positive for antinuclear antibodies. Erosive changes were reported on radiographs in a significantly greater number of children with A-DS (42%) than with children with JIA (14%; P <.05). In the majority of A-DS cases, erythrocyte sedimentation rate and C-reactive protein levels were not helpful in arriving at a diagnosis.
These data support the addition of a musculoskeletal examination to the health surveillance guidelines for children with Down syndrome. Investigators also proposed a new clinical term to better capture A-DS: “DS-associated arthritis.” Further research in a larger cohort is necessary to describe the pathogenesis of DS-associated arthritis and to identify biomarkers.
Foley C, Deely D, MacDermott EJ, Killeen O. Arthropathy of Down syndrome: an under-diagnosed inflammatory joint disease that warrants a name change. Presented at: 2019 ACR/ARP Annual Meeting; November 8-13, 2019; Atlanta, GA. Abstract 1817.