A case of multicentric carpotarsal osteolysis detected with infection by chance

Abstract

We experienced a case of multicentric carpotarsal osteolysis (MCTO) diagnosed based on genetic testing at an early stage, leading to useful management. She was a 1-year-old girl with a history of laryngomalacia, short skull, dysphagia, and psychomotor retardation. When she was admitted to the hospital for treatment of pneumonia and bronchial asthma attacks, she met the diagnostic criteria for nephrotic syndrome. Then, steroid therapy was started but she was found to be steroid resistant. Renal ultrasonography revealed the presence of nephronophthisis, and a renal biopsy was performed. Renal pathology showed compatible findings with nephronophthisis and secondary focal segmental glomerulosclerosis (FSGS). On the other hand, genetic testing showed a previously reported heterozygous mutation in the MAFB gene and she was finally diagnosed with MCTO. Radiographic examination revealed osteolysis characteristic of MCTO, and orthopedic management was initiated. During outpatient management, renal dysfunction rapidly progressed and peritoneal dialysis was required at the age of three. There is no report of MCTO with nephrotic state, and early genetic diagnosis was useful for long-term management.