Progressive osseous heteroplasia: diagnosis, treatment, and prognosis

Abstract

Robert J Pignolo,1–3 Girish Ramaswamy,2,3 John T Fong,2,3 Eileen M Shore,2–4 Frederick S Kaplan1–3 1Department of Medicine, 2Department of Orthopaedic Surgery, 3The Center for Research in FOP and Related Disorders, 4Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA Abstract: Progressive osseous heteroplasia (POH) is an ultrarare genetic condition of progressive ectopic ossification. Most cases of POH are caused by heterozygous inactivating mutations of GNAS, the gene encoding the alpha subunit of the G-stimulatory protein of adenylyl cyclase. POH is part of a spectrum of related genetic disorders, including Albright hereditary osteodystrophy, pseudohypoparathyroidism, and primary osteoma cutis, that share common features of superficial ossification and association with inactivating mutations of GNAS. The genetics, diagnostic criteria, supporting clinical features, current management, and prognosis of POH are reviewed here, and emerging therapeutic strategies are discussed. Keywords: progressive osseous heteroplasia, GNAS, heterotopic ossification