ESPE Abstracts

Pseudohypoparathyroidism (PHP) is a disorder of hormone resistance characterized by end-organ resistance to the actions of parathyroid hormone (PTH). The resistance primarily occurs in the renal proximal tubule, thus leading to hypocalcemia, hyperphosphatemia, and elevated serum PTH. Indicating the resistance in this tissue, patients with PHP show blunted phosphate excretion in response to exogenously administered PTH. In PHP type I, the patients additionally demonstrate blunt...

Endochondral bone formation regulates bone growth both during embryonic development and after birth. Several different autocrine/paracrine or hormonal mechanisms govern the regulation of endochondral bone formation. Among those is the pathway involving stimulatory G protein, which primarily mediates the actions of parathyroid hormone-related peptide (PTHrP) in the growth plate. PTHrP is synthesized in the perichondrial cells and chondrocytes at the end of bones. In the growing...

Autosomal dominant pseudohypoparathyroidism type-Ib is characterized by renal parathyroid hormone resistance, with resultant hypocalcemia and hyperphosphatemia. This disorder is associated with an isolated loss of methylation at GNAS exon A/B and most patients carry maternal microdeletions in the neighboring STX16 gene. The shortest deletion overlap is a 1.2-kb region spanning STX16 exon 4 and thought to harbor a cis-acting element regulating GNAS A/B methylation. However, abl...

Pseudohypoparathyroidism (PHP) and related disorders lead to a wide spectrum of abnormal physical characteristics, neurocognitive and endocrine abnormalities. PHP (including all subtypes), pseudoPHP, acrodysostosis and progressive osseous heteroplasia refer to heterogeneous disorders characterized by physical findings, differently associated in each subtype, including short bones, short stature, stocky build, subcutaneous ectopic ossifications, as well as laboratory abnormalit...