Hereditary hypophosphatemia in Norway: a retrospective population-based study of genotypes, phenotypes, and treatment complications
Open Access
- 1 February 2016
- journal article
- Published by Oxford University Press (OUP) in Acta Endocrinologica
- Vol. 174 (2), 125-136
- https://doi.org/10.1530/eje-15-0515
Abstract
Objective: Hereditary hypophosphatemias (HH) are rare monogenic conditions characterized by decreased renal tubular phosphate reabsorption. The aim of this study was to explore the prevalence, genotypes, phenotypic spectrum, treatment response, and complications of treatment in the Norwegian population of children with HH.Design: Retrospective national cohort study.Methods: Sanger sequencing and multiplex ligand-dependent probe amplification analysis ofPHEXand Sanger sequencing ofFGF23,DMP1,ENPP1KL, andFAM20Cwere performed to assess genotype in patients with HH with or without rickets in all pediatric hospital departments across Norway. Patients with hypercalcuria were screened forSLC34A3mutations. In one family, exome sequencing was performed. Information from the patients' medical records was collected for the evaluation of phenotype.Results: Twety-eight patients with HH (18 females and ten males) from 19 different families were identified. X-linked dominant hypophosphatemic rickets (XLHR) was confirmed in 21 children from 13 families. The total number of inhabitants in Norway aged 18 or below by 1st January 2010 was 1 109 156, giving an XLHR prevalence of ∼1 in 60 000 Norwegian children.FAM20Cmutations were found in two brothers andSLC34A3mutations in one patient. In XLHR, growth was compromised in spite of treatment with oral phosphate and active vitamin D compounds, with males tending to be more affected than females. Nephrocalcinosis tended to be slightly more common in patients starting treatment before 1 year of age, and was associated with higher average treatment doses of phosphate. However, none of these differences reached statistical significance.Conclusions: We present the first national cohort of HH in children. The prevalence of XLHR seems to be lower in Norwegian children than reported earlier.Keywords
This publication has 84 references indexed in Scilit:
- Inactivation of a Novel FGF23 Regulator, FAM20C, Leads to Hypophosphatemic Rickets in MicePLoS Genetics, 2012
- Genetic diagnosis of X-linked dominant hypophosphatemic rickets in a cohort study: Tubular reabsorption of phosphate and 1,25(OH)2D serum levels are associated with PHEX mutation typeBMC Medical Genetics, 2011
- A clinician's guide to X-linked hypophosphatemiaJournal of Bone and Mineral Research, 2011
- Treatment of X-Linked Hypophosphatemia with Calcitriol and Phosphate Increases Circulating Fibroblast Growth Factor 23 ConcentrationsJournal of Clinical Endocrinology & Metabolism, 2010
- Autosomal-Recessive Hypophosphatemic Rickets Is Associated with an Inactivation Mutation in the ENPP1 GeneAmerican Journal of Human Genetics, 2010
- Loss-of-Function ENPP1 Mutations Cause Both Generalized Arterial Calcification of Infancy and Autosomal-Recessive Hypophosphatemic RicketsAmerican Journal of Human Genetics, 2010
- Calcimimetics as an Adjuvant Treatment for Familial Hypophosphatemic RicketsClinical Journal of the American Society of Nephrology, 2008
- A translocation causing increased α-Klotho level results in hypophosphatemic rickets and hyperparathyroidismProceedings of the National Academy of Sciences of the United States of America, 2008
- Loss of DMP1 causes rickets and osteomalacia and identifies a role for osteocytes in mineral metabolismNature Genetics, 2006
- FGF-23 Is a Potent Regulator of Vitamin D Metabolism and Phosphate HomeostasisJournal of Bone and Mineral Research, 2004