Endocrine Abstracts

Pseudohypoparathyroidism type 1B (PHP-1B) is a rare, familial or sporadic, imprinting disorder due to the epigenetic dysregulation of the GNAS locus, whose main product is the α subunit of the stimulatory G protein (Gsα). Sporadic PHP-1B cases (spor-PHP-1B) display broad methylation abnormalities at multiple GNAS DMRs, but the underlying molecular mechanism is still unknown.Classically, PHP-1B patients show PTH and TSH resistance, but, in the p...

The term pseudohypoparathyroidism (PHP) defines a heterogeneous group of rare, related and deeply impairing metabolic diseases due to end-organ resistance to the actions of PTH, associated to molecular defects at the GNAS locus. Different subtypes of PHP have been described based on the existence of additional clinical features, such as resistance to other hormones acting via GPCRs and Albright’s hereditary osteodystrophy (AHO). Recently, the detection in a small subset o...

Epi/genetic defects at the imprinted GNAS locus, that encodes the α subunit of the stimulatory G protein (Gsα), have been associated with a heterogeneous group of rare diseases, termed as Pseudohypoparathyroidism. Most GNAS-based disorders have the common feature of episodic de novo formation of heterotopic ossifications (HO) in subcutaneous tissues. The mosaic tissue distribution of HO suggests that pathogenesis involves an abnormal differentiation of precu...

Progressive osseous heteroplasia (POH) is a rare autosomal dominant disorder of mesenchymal differentiation characterized by progressive heterotopic ossification (HO) of dermis, skeletal muscle and deep connective tissues. Initially HO occurs during infancy as osteoma cutis, then extends progressively into deep connective tissues during childhood. Most cases of POH are caused by paternally inherited mutations of GNAS gene. Maternal mutations as well as epigentic defec...

The clinical condition resulting from end-organ resistance to parathormone (rPTH), caused by (epi)genetic alterations of GNAS, was termed as Pseudohypoparathyroidism (PHP). The high phenotype heterogeneity, the existence of additional clinical features such as resistance to other hormones (TSH/GHRH/gonadotropins) and Albright’s hereditary osteodystrophy (AHO), led to the distinction of specific PHP subtypes.The purpose of the present work is to prov...

Background: Disorders caused by impairments in the parathyroid hormone (PTH) signaling pathway are historically classified under the term pseudohypoparathyroidism (PHP), that encompasses rare, related but highly heterogeneous diseases with demonstrated (epi)genetic causes. The actual classification is based on the presence or absence of specific clinical and biochemical signs together with an in vivo response to exogenous PTH and the results of an in vitro as...