Active clinical trials for "Familial Hypophosphatemic Rickets"

Fibroblast growth factor 23 (FGF23) is the cornerstone of phosphate / calcium / vitamin D metabolism: it is synthesized mainly by osteocytes and acts as a Phosphating agent, inhibitor of dihydroxyvitamin D, and inhibitor of synthesis and secretion of Parathyroid hormone (PTH) in most tissues. The specific role of FGF23 on bone has yet to be demonstrated. In some diseases such as hypophosphatemic rickets (HR), the direct role of FGF23 on bone has not yet been studied to our knowledge, whereas these genetic hypophosphatemias are secondary to overexpression of FGF23, whether an activating mutation of FGF23 or inhibitory mutations of its inhibitors (Dentin matrix acidic phosphoprotein 1 (DMP1) and Phosphate-regulating neutral endopeptidase, X-linked (PHEX)). However, patients with X-linked hypophosphatemic rickets (XLH) have higher circulating FGF23 levels than healthy controls and these levels are higher in treated patients. Management of XLH consists primarily of correcting the native vitamin D defect by prescribing active vitamin D analogs as well as phosphate supplementation to improve bone mineralization and decrease dental complications, growth, and bone deformities. Recently, a new therapeutic option has been developed for XLH, burosumab, a human monoclonal antibody that binds and inhibits FGF23 activity. The use of burosumab is currently authorized in France in some pediatric patients with severe forms of XLH. Independently of the indirect bone effects of phosphate correction and vitamin D levels, the direct role of burosumab on bone cells has never been studied. The objective of this project is to study the osteoclastic biology of patients with HR compared to control patients, and to evaluate the direct impact of the treatments used in this pathology on human osteoclasts.

This study aims to provide Health-related Quality of Life (HRQoL) data from children and adolescents with growing skeletons in the United Kingdom (UK), including those treated with burosumab or alternative XLH treatment, as part of an updated submission to the SMC in early 2023. This study will utilise data from a subset of UK sites already within the XLH Registry (including participating Scottish sites) and collect additional HRQoL data within these sites (that are otherwise not included in the wider XLH Registry protocol). The HRQoL data will enable the calculation of HRQoL to derive the HRQoL utility estimates in children and adolescents with growing skeletons for the RSS health states, hence addressing an area of uncertainty.

This study aimed to characterize foot pathologies using X-rays and clinical examination and assess related outcome scores in adolescents and adults with X-linked Hypophophatemia

To date, the investigators lack characterization of, the burden of, and the systemic progression of disease in ENPP1 deficiency and ABCC6 deficiency from a patient and/or parent perspective. This study aims to document this characterization, progression as well as the burden of disease. Link to the study registration- https://www.engagehealth.com/survey/TakeSurvey.aspx?SurveyID=8252n62

Individual patient expanded access requests may be considered for patients who have no other treatment options

The purpose of the study is to do a follow-up survey of all individuals with hereditary hypophosphatemia in Norway, focusing on manifestations in childhood and adolescence. The investigators also want to study phenotype-genotype associations, and look for new genes, in all forms of hereditary hypo and hyperphosphatemia.

Generalized arterial calcification of infancy (GACI) is an ultra-rare disorder with an estimated birth prevalence of around 1 in 400,000.1 GACI is generally fatal before birth or within the first six months after birth. The cause of death is frequently myocardial infarction or stroke. GACI is strongly associated with inactivating mutations in ectonucleotide pyrophosphate/ phosphodiesterase 1 (ENPP1). Many patients with GACI, including some without an ENPP1 mutation also present with mutations in adenosine triphosphate binding cassette transporter protein subfamily C member 6 (ABCC6). Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) and pseudoxanthoma elasticum (PXE) are believed to be closely related to GACI. ARHR2 is caused by mutations in the ENPP1 gene and PXE is caused by mutations in the ABCC6 gene, with both being observed among patients with GACI. The natural history of GACI and in particular its long term morbidity and mortality are poorly understood. The primary objective of this study is to characterize overall survival among patients with GACI, over time from birth.