Abstract
Multicentric carpotarsal osteolysis (MCTO) is a rare skeletal dysplasia characterized by osteolysis of the carpal and tarsal bones. Antiresorptive agents have proven ineffective and the pathogenesis of MCTO remains poorly understood. We report a young child with a novel variant in MAFB who demonstrated clinical improvement of joint symptoms following anti-rheumatic therapies. Also, radiographs from a young age suggest that dysfunctional bone formation may play a role in the skeletal phenotype of MCTO.