A rare type of skeletal dysplasia resembling rheumatoid arthritis

Abstract

Abstract Progressive pseudorheumatoid dysplasia is a rare type of spondylo-epi-metaphyseal dysplasia that can be confused clinically and radiologically with juvenile idiopathic arthritis. Precise diagnosis is essential to avoid unnecessary investigation and treatment. The disease is characterized by predominant involvement of joints with progressive limitation of movement with absence of clinical and biochemical markers of inflammation. Here we report three children (two boys and one girl) with this rare disease. Their age of presentation ranged from 3-5 years with pain, swelling and deformities of interphalangeal joints of both hands which progressed with time to joint contractures. Other affected joints included elbows and knees. Back was involved in the oldest patient with lumbar lordosis. All three patients had short stature and normal mentality. The patients had several misdiagnoses before referral to the genetics clinic including rheumatoid arthritis and Morquio syndrome which was excluded by proper investigations. In conclusion, Progressive pseudorheumatoid dysplasia can be confused with Juvenile rheumatoid arthritis as well as other MPS diseases, both clinically and radiologically. Early diagnosis is mandatory to avoid associated disabilities and to avoid unnecessary investigations and treatment