Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) due to ENPP1-deficiency.

Jakob Höppner, Uwe Kornak, Kathrin Sinningen, Frank Rutsch, Ralf Oheim, Corinna Grasemann

Journal: Bone 2021;153():116111

PMID: 34252603

Free Full Text on Elsevier Science View on PubMed

Abstract

Awareness for hypophosphatemic rickets has increased in the last years, based on the availability of specific medical treatments. Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) is a rare form of hypophosphatemic rickets, which is known to develop in survivors of generalized arterial calcification of infancy (GACI). Both disorders are based on a deficiency of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and present with a high clinical variability and a lack of a phenotype-genotype association. ARHR2 is characterized by phosphate wasting due to elevated fibroblast growth factor 23 (FGF23) levels and might represent a response of the organism to minimize ectopic calcification in individuals with ENPP1-deficiency. This report reviews the recent clinical and preclinical data on this ultra-rare disease in childhood.

Address: Center for Rare Diseases Ruhr CeSER, Ruhr-University Bochum and Witten/Herdecke University, Germany; Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany.; Institute for Human Genetics, Universitätsmedizin Göttingen, Göttingen, Germany.; Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany.; Department of General Pediatrics, Münster University Children's Hospital, Münster, Germany.; Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.; Center for Rare Diseases Ruhr CeSER, Ruhr-University Bochum and Witten/Herdecke University, Germany; Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany. Electronic address: [email protected].

DOI: 10.1016/j.bone.2021.116111