ESPE Abstracts

Background: Hypophosphatemic rickets (HHR) is a vitamin D-resistant rickets and results in children in variable degrees of delayed walking, waddling gait, leg bowing, enlarged cartilages, bone pain, craniostenosis and growth failure. There are both inherited and acquired forms, where FGF23-dependent forms with X-linked dominant hypophosphatemic rickets (XLH) head of the list is the most prevalent genetic form; molecular defects of the sodium-phosphate co-trans...

Background: Pseudohypoparathyroidism (PHP) is characterized by proximal tubular resistance to PTH and, in some disease variants, by Albright osteodystrophy. PHP is caused either by mutations in those regions of GNAS encoding Gsα (PHP1A and PseudoPHP) or by GNAS methylation defects (autosomal dominant (AD) and sporadic (spor) PHP1B). Phenotypic differences in fetal growth, post-natal growth and metabolism are observed in the different PHP types.<p cla...

Background: In humans, activating mutations in the PRKAR1A gene cause acrodysostosis1 (ACRDYS1). Two striking features of this rare developmental and skeletal disorder are renal resistance to PTH and chondrodysplasia resulting from the constitutive inhibition of PTHR1/Gsa/AC/cAMP/PKA signaling caused by the PRKAR1A mutations.Objective and hypotheses: Document the consequences of the germline expression of a PRKAR1A mutation causing a dominant repression ...

Background: Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a very rare clinical condition. Patients suffer from hyponatremia, hypo-osmolality with inappropriately elevated urinary osmolality and undetectable AVP levels. Activating mutations of AVPR2, the vasopressin receptor type 2 (V2R), induce a prolonged signaling of the intracellular cAMP/PKA pathway and cause NSIAD in patients.Objective and hypotheses: To describe a new phenotype in a...

Background: Hereditary Hypophosphatemic Rickets (HHR) is caused by persistently elevated FGF23 resulting in renal phosphate wasting and decreased 25 vitamin D hydroxylation. Treatment with vitamin D analogues (VDA) has been added to phosphate supplements in the late seventies.Objective and hypotheses: Our objective was to evaluate the outcomes of VDA and phosphate supplements in adult patients with HHR in comparison with patients who did not receive VDA ...

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...

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...

Background: MODY is characterised by an early onset of diabetes and a positive family history of diabetes with an autosomal dominant mode of inheritance. We report a 15 year girl with a HNF1A mutation who presented with MODY without a positive family history.Objective and hypotheses: HNF1A-MODY is often misdiagnosed as type 1 or type 2 diabetes. Genetic confirmation of MODY in insulin-treated patients helps in making changes in the treatment modality as ...

Disorders of sex development (DSD) constitute an array of rare disorders affecting the genito-urinary tract and the endocrine-reproductive system and are often identified in the newborn or adolescent. Gene mutations causing DSD are slowly being identified using high-throughput sequencing, but the interpretation of the data and ascribing causality to novel variants is challenging. This is because DSD mutations occur in multiple genes with each gene affecting a small number of i...

Background: Neonatal hyperthyrotropinaemia (HT) is defined by elevated TSH and normal fT4. HT is an increasingly common diagnosis and may be transient or permanent. There is a often a diagnostic dilemma whether to treat to prevent subclincal hypothyroidism or to wait thereby avoiding the risks of iatrogenic hyperthyroidism.Objective and hypotheses: To examine a large population of infants referred to a tertiary centre over one year and determi...