title: Pseudohypoparathyroidism type Ib in 2015.
abstract: The term pseudohypoparathryoidism (PHP) refers to a group of rare genetic and epigenetic disorders characterized by resistance to the action of parathyroid hormone (PTH) that activates cAMP signaling in target cells. Together with pseudohypoparathyroidism, Albright hereditary osteodystrophy (AHO) and progressive osseous heteroplasia (POH) represent rare, related and deeply impairing disorders encompassing heterogeneous features, such as brachydactyly, ectopic ossifications, short stature, mental retardation and endocrine deficiencies due to resistance to the action of different hormones. The two main subtypes, PHP-Ia and PHP-Ib, are caused by mutations in GNAS exons 1-13 and methylation defects in the imprinted GNAS cluster respectively, while mutations in the PRKAR1A and PDE4D genes (also involved in mediating cAMP signalling) have been demonstrated in patients with acrodysostosis, a disease of bone formation with characteristics similar to AHO. The molecular overlap among these disorders indicates the need for different classification models and seriously alters our understanding of the mechanisms through which GNAS defects, together with the new recently described defects involving other components of the cAMP signalling cascade, cause AHO-related disorders.
authors.affiliation: Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy. Electronic address: giovanna.mantovani@unimi.it.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Mantovani
authors.affiliation: Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy.
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Elli
mesh_terms: D002864:Chromogranins; D018450:Disease Progression; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000235:genetics; D006801:Humans; D011547:Pseudohypoparathyroidism / Q000235:genetics* / Q000473:pathology*; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000235:genetics
chemical_list: D002864:Chromogranins; C473449:PTH1R protein, human; D044168:Receptor, Parathyroid Hormone, Type 1; C406732:GNAS protein, human; D019205:GTP-Binding Protein alpha Subunits, Gs
keywords: Albright hereditary osteodystrophy; Empreinte; GNAS; Imprinting; Ostéodytrophie héréditaire d’Albright; Pseudohypoparathyroidism; Pseudohypoparathyroïdie