ESPE Abstracts

Introduction: Despite the high detection rate of GNAS molecular defects, about 30% of patients with a clinical suspect of PHP/AHO still lack a confirming molecular diagnosis. Mutations in genes encoding proteins crucial for cAMP-mediated signaling have been recently detected in a small subset of patients negative for GNAS defects, showing a phenotypic overlap between PHP and Acrodysostosis.Clinical case pres...

Background: Genetic and epigenetic alterations at the GNAS locus are responsible for the Gsα protein dysfunctions causing Pseudohypoparathyroidism (PHP), a heterogeneous disease characterized by multiple hormone resistances and AHO signs (short stature, obesity, round face, brachydactyly, subcutaneous ossifications and mental retardation). A clinical overlap among molecular subtypes of the disease (Ia, Ib, Ic and II) makes the current classification inadequate; furthermor...

Since the first description of pseudohypoparathyroidism (PHP), a remarkable clinical variability, which translates in several PHP subtypes, was observed. In 2016 a new classification of this group of diseases have been published by the European Network on PHP and related disorders, proposing “inactivating PTH/PTHrP signaling disorder” (iPPSD) as a new term that encompasses all the clinical entities, stressing the common mechanism responsible for all diseases. iPPSDs ...

Background: Pseudohypoparathyroidism type 1A (PHP1A) and PseudoPHP are caused respectively by maternal and paternal mutations involving those GNAS exons that encode the alpha-subunit of the stimulatory G protein (Gsα). Common to different forms of PHP1B is a loss-of-methylation (LOM) at one or several maternal GNAS exons, which likely reduces Gsα expression in certain tissues. In most autosomal dominant PHP1B variants (AD-PHP1B), LOM is restricted t...

Background: Sporadic pseudohypoparathyroidism type Ib (spor-PHP-Ib) is caused by GNAS methylation alterations with loss of imprinting at the exon A/B differentially methylated region (DMR), without genetic deletions disrupting the STX16 ICR. These patients classically display hormone resistance limited to PTH and TSH with no Albright hereditary osteodistrophy (AHO).Objective and hypotheses: We describe two cases with the same imprinting methylat...

Introduction: Children born small for gestational age (SGA) represent a heterogeneous population, displaying different phenotypes for both growth and metabolic status. Low birth length and/or weight increases the risks for not only growth impairment but also for metabolic derangements (cardiovascular disease, hypertension and type 2 diabetes), the latter with an even amplified risk in children with rapid postnatal weight gain. Variability in metabolic paramete...

Background: Pseudohypoparathyroidism 1A, newly classified as inactivating PTH/PTHrP signaling disorder type 2 (iPPSD2), is defined by resistance to parathyroid hormone, short stature and early-onset obesity. Short stature is caused by skeletal dysplasia and additionally, in some cases, also by the coexistence of growth hormone deficiency, as other hormonal resistances might be present (e.g. thyroid-stimulating hormone, growth hormone releasing hormone (GHRH), ...

Classic features of inactivating PTH/PTHrP Signaling Disorder 2 or 3 (iPPSD2, iPPSD3), i.e. former pseudohypoparathyroidism include multi-hormone resistance, short stature, subcutaneous ossifications, brachydactyly, and early-onset obesity and a molecular defect at the GNAS region. In addition, patients may present with less-known features including craniosynostosis (CSO).Objective: To describe the prevalence of CSO in a cohort ...

Background: A new classification of pseudohypoparathyroidism is available (Thiele et al. 2016, J Endocrinol). The phenotype variability of inactivating PTH/PTHrP Signaling Disorders (iPPSD, former pseudohypoparathyroidism) cases is still very challenging, even for experts. Thus, it is crucial to collect data in a centralized manner for future investigation.Methods: The EuRRECa/EuRR-Bone registries are the first ...

Background: Disorders related to an impairment in parathyroid hormone (PTH) signaling pathway are historically classified under the term pseudohypoparathyroidism (PHP), that now 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 an in vitro assay of Gs&#9...