Differential diagnosis of juvenile idiopathic arthritis and multiple epiphyseal dysplasia: Experience of multidisciplinary interaction

Introduction . Juvenile idiopathic arthritis (JIA) is a common multifactorial disease characterized by the presence of chronic inflammation in the joints, entheses and other structures of the musculoskeletal system in combination with a certain range of extraskeletal disorders. Vast variety of JIA clinical variants and the variability of the disease course make primary and differential diagnosis difficult, which often leads to a delayed start of treatment and an inadequate choice of medical therapy or, conversely, an excess of medication. In the range of differential diagnostic conditions that have similar symptoms and are manifested by severe arthralgia, gait disturbance, joint stiffness, as well as the presence of effusion and gradual progression of bone destruction mainly in the epiphyseal plate, one should remember about hereditary skeletal dysplasias, primarily from a genetically heterogeneous group of multiple epiphyseal dysplasias (MED). The aim of the study – description of the clinical and genetic characteristics of three patients with various genetic variants of MED and defining approaches for their differential diagnosis with JIA. Materials and methods . There were three patients from three unrelated families aged from 7 to 13 years old under our supervision. To clarify the diagnosis, a genealogical analysis, a clinical examination of patients and first-degree relatives, as well as an assessment of X-ray images of long tubular bones were carried out. Molecular genetic confirmation of the MED diagnosis types 1 and 2 was based on the results of custom panel sequencing consisting of 166 genes responsible for the development of hereditary skeletal pathology. To clarify the molecular genetic diagnosis of MED type 4, an analysis of the SLC26A2 gene was performed using automated Sanger sequencing. Results . Anamnestic, clinical, radiological, and molecular genetic characteristics of three unrelated patients with different genetic types of MED caused by variants in the COMP , SLC26A2 , and COL9A2 genes were analyzed. The first symptoms of the disease in observed patients with three different genetic variants of MED occurred at the age of 2–3 years old and were characterized by gait disturbance and climbing stairs difficulties. Gradually, these symptoms were accompanied by pain in large joints. According to the ultrasound examination of the joints, signs of synovitis were noted, as a result they were diagnosed with JIA (polyarticular variant, seronegativ