Multicentric carpo-tarsal osteolysis syndrome (MCTO;OMIM#166300) is an ultrarare autosomal dominant skeletal disorder caused by mutations in the MAFB gene (v-maf musculoaponeurotic fibrosarcoma oncogene ortholog B), with high frequency of sporadic cases [1]. This evidence concerns the gene MAFB and multicentric carpo-tarsal osteolysis with or without nephropathy.