ESPE Abstracts

Background: Disproportionate short stature is seen in most individuals with X-linked hypophosphatemia (XLH). Vitamin D and phosphate supplementation can improve growth slightly. Burosumab showed minimal improvement of growth in older children. No growth data of XLH children that started burosumab at a very young age, i.e., between 1 and 4 years, are available.Methods: We included 17 XLH children (11 boys) who started bur...

Introduction: Idiopathic short stature (ISS) is characterized by a reduced height (at least 2 standard deviation scores [SDS]) from expected norms based on age, sex, and population-specific height standards in the absence of growth hormone (GH) deficiency or other known etiologies. ISS is a registered indication for GH therapy in USA but not in Europe. The psychosocial burden of ISS remains underexplored, including its impact on quality of life. Using National...

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), ...

In XLH, excess fibroblast growth factor 23 (FGF23) causes hypophosphatemia and consequent rickets, skeletal deformities, and growth impairment. The efficacy and safety of burosumab, a fully human monoclonal antibody against FGF23, was evaluated in two Phase 2 trials in children with XLH. In CL201, 52 children with XLH (5–12 years old, Tanner ≤2) were randomized 1:1 to receive subcutaneous burosumab every 2 (Q2W) or 4 (Q4W) weeks, with doses titrated up to 2 mg/kg to...

Mineralization defects and paradoxical mineralizing enthesopathies are hallmarks of X-linked Hypophosphatemia (XLH), a rare skeletal disease caused by inactivating mutations in the PHEX gene (Phosphate-regulating endopeptidase homolog, X-linked). The current medical treatment, which consist in oral phosphorus supplementation and active vitamin D analogues, aimed at counteracting consequences of FGF23 excess and is commonly prescribed from early childhood to the end of...

Hypophosphatasia (HPP) is a rare, inherited, systemic disease caused by mutation(s) of the ALPL gene encoding tissue-nonspecific alkaline phosphatase (ALP), resulting in deficient ALP activity. Asfotase alfa is an enzyme replacement therapy approved for treatment of patients with pediatric-onset HPP. The global HPP Registry is an observational, prospective, multinational study (NCT02306720; EUPAS13514) established to collect real world clinical data from patients of a...

Introduction: X-linked hypophosphatemia (XLH) is a rare, inherited disease that affects approximately 1 in 20,000 individuals. XLH is a disorder of renal phosphate wasting caused by high circulating levels of fibroblast growth factor 23 (FGF23) that impairs normal phosphate reabsorption in the kidney and production of the active form of vitamin D. Children with XLH experience abnormal bone development, rickets, osteomalacia, impaired growth, dental abscesses, craniosynostosis ...

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 a rare genetic disease characterized by renal phosphate wasting, caused by elevated circulating FGF23. Despite the current available treatment complications include short stature, hyperparathyroidism, pseudofractures, bone pain, bone demineralization and osteoporosis, nephrocalcinosis and enthesopathies. Elevated circulating FGF23 was recently involved in glucose metabolism and cardiovascular function.<p class="abste...

Background: Hypophosphatasia (HPP) is a rare, inherited metabolic disease characterised by bone mineralisation defects and osteomalacia, and systemic manifestations, including seizures, respiratory insufficiency, muscle weakness, nephrocalcinosis, and pain. The biochemical hallmark of HPP is low serum alkaline phosphatase activity, resulting from loss-of-function mutations in the gene encoding tissue non-specific alkaline phosphatase. HPP presents a broad spectrum of disease s...