Abstract: Objective To explore the clinical and genetic characteristics of multicentric carpotarsal osteolysis (MCTO). Methods The clinical data of a MCTO patient was retrospectively analyzed and related literature was reviewed. Results The patient is a 12 years and 3 months old girl, initially suffered from swelling and pain in the left ankle, wrist, and metacarpophalangeal joints at age of 3 years and 3 months. She was diagnosed with juvenile idiopathic arthritis (JIA) and received long-term antirheumatic treatment but with few effects. Subsequently, she presented with shortened left arm. She developed persistent proteinuria 2 years ago. Imaging examination indicated bone destruction of the left carpal and left wrist. Whole exome sequencing revealed a heterozygous mutation of c. 206 c > T (p.S 69 L) in MAFB gene and the diagnosis of MCTO was made. Electronic systemic searches were conducted in PubMed, Wanfang, and CNKI databases, and 15 articles were selected. We reviewed 60 patients including this case. Carpus ( 100 %), phalanges ( 94 . 1 %), elbow joints ( 64 . 7 %), knee joints ( 44 . 1 %), hip joints ( 14 . 7 %), and shoulder joints ( 8 . 8 %) were commonly involved. Forty-one patients had kidney involvement of different degrees, and 13 patients received kidney transplantation. At present, a total of 18 missense mutations have been reported. Conclusion Patients with MCTO are characterized by progressive osteolytic diseases of the carpus and tarsal bones, which can be confused with JIA. Patients may present with proteinuria in the early stage followed by progressive renal failure. The genetic test is essential for diagnosis.

Key words: multiple osteolysis syndrome; proteinuria; MAFB gene; rare diseases