Pseudohypoparathyroidism and Gsα-cAMP-linked disorders: current view and open issues.
Pseudohypoparathyroidism exemplifies an unusual form of hormone resistance as the underlying molecular defect is a partial deficiency of the α subunit of the stimulatory G protein (Gsα), a key regulator of the cAMP signalling pathway, rather than of the parathyroid hormone (PTH) receptor itself. Despite the first description of this disorder dating back to 1942, later findings have unveiled complex epigenetic alterations in addition to classic mutations in GNAS underpining the molecular basis of the main subtypes of pseudohypoparathyroidism. Moreover, mutations in PRKAR1A and PDE4D, which encode proteins crucial for Gsα-cAMP-mediated signalling, have been found in patients with acrodysostosis. As acrodysostosis, a disease characterized by skeletal malformations and endocrine disturbances, shares clinical and molecular characteristics with pseudohypoparathyroidism, making a differential diagnosis and providing genetic counselling to patients and families is a challenge for endocrinologists. Accumulating data on the genetic and clinical aspects of this group of diseases highlight the limitation of the current classification system and prompt the need for a new definition as well as for new diagnostic and/or therapeutic algorithms. This Review discusses both the current understanding and future challenges for the clinical and molecular diagnosis, classification and treatment of pseudohypoparathyroidism.
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy.
Giovanna
G
Mantovani
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy.
Anna
A
Spada
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy.
Francesca Marta
FM
Elli
D001851:Bone Diseases, Metabolic / Q000175:diagnosis / Q000235:genetics; D002864:Chromogranins / Q000235:genetics*; D002872:Chromosome Deletion; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D000242:Cyclic AMP; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit / Q000235:genetics; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000235:genetics; D003937:Diagnosis, Differential; D004413:Dysostoses / Q000175:diagnosis / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics*; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000235:genetics; D009999:Ossification, Heterotopic / Q000175:diagnosis / Q000235:genetics; D010009:Osteochondrodysplasias / Q000175:diagnosis / Q000235:genetics; D011547:Pseudohypoparathyroidism / Q000145:classification / Q000175:diagnosis / Q000235:genetics*; D015398:Signal Transduction; D012873:Skin Diseases, Genetic / Q000175:diagnosis / Q000235:genetics
D002864:Chromogranins; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; C517834:PRKAR1A protein, human; D000242:Cyclic AMP; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517376:PDE4D protein, human; C406732:GNAS protein, human; D019205:GTP-Binding Protein alpha Subunits, Gs