Panostotic expansile bone disease with massive jaw tumor formation and a novel mutation in the signal peptide of RANK

Journal of Bone and Mineral Research, 09/30/2013

Precise regulation of bone resorption is critical for skeletal homeostasis. The authors report a 32–year–old man with a panostotic expansile bone disease and a massive hemorrhagic mandibular tumor. Originally from Mexico, he was deaf at birth and became “bow–legged” during childhood. There was no family history of skeletal disease. Puberty occurred normally, but during adolescence, he experienced difficulty straightening his limbs, sustained multiple fractures, and developed a bony tumor on his chin. They found a unique 12 base–pair duplication in the signal peptide of TNFRSF11A, the gene that encodes RANK. No exon or splice site mutations were found in the genes encoding RANK–ligand or osteoprotegerin. Alendronate followed by pamidronate therapies substantially decreased his serum alkaline phosphatase activity. This unique patient expands the known phenotypes of the disorders of RANK signaling activation.

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