MP10-16 VITAMIN D SUPPLEMENTATION MAY CAUSE KIDNEY STONES - WHAT IS THE RISK? LESSONS FROM IDIOPATHIC INFANTILE HYPERCALCEMIA AND CYP24A1

Abstract

You have accessJournal of UrologyCME1 Apr 2023MP10-16 VITAMIN D SUPPLEMENTATION MAY CAUSE KIDNEY STONES - WHAT IS THE RISK? LESSONS FROM IDIOPATHIC INFANTILE HYPERCALCEMIA AND CYP24A1 Alicja Tomaszewski, Cindy Lin, Joshua Chang, Katreya Lovrenert, John Weaver, Jessica Hannick, Lynn Woo, and Chen-Han Wilfred Wu Alicja TomaszewskiAlicja Tomaszewski More articles by this author , Cindy LinCindy Lin More articles by this author , Joshua ChangJoshua Chang More articles by this author , Katreya LovrenertKatreya Lovrenert More articles by this author , John WeaverJohn Weaver More articles by this author , Jessica HannickJessica Hannick More articles by this author , Lynn WooLynn Woo More articles by this author , and Chen-Han Wilfred WuChen-Han Wilfred Wu More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003225.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Vitamin D is used to treat rickets, and has been proposed to reduce risk of osteoporosis, fractures, multiple sclerosis, and other conditions. However, it is contraindicated in people with infantile idiopathic hypercalcemia (IIH). IIH is a rare autosomal recessive disorder caused by impaired 24-hydroxylase enzyme activity encoded by the CYP24A1 gene; patients present with hypercalcemia from increased calcium absorption, increased osteoclast activity, and decreased calcium excretion, and vitamin D supplementation causes nephrolithiasis and nephrocalcinosis. The clinical prevalence of IIH is unknown. This study seeks to characterize the prevalence of IIH caused by frequencies of pathogenic variants in CYP24A1, which can improve screening and prevent complications from inappropriate vitamin D supplementation. METHODS: Known pathogenic variants of CYP24A1 causing IIH were generated from the Human Gene Mutation Database (HGMD). The 1000 Genomes (1KG) database was used to identify healthy individuals with CYP24A1 variants. HGMD and 1KG databases were intersected to find shared variants, and prevalence was calculated using the Hardy-Weinberg equation. RESULTS: After intersecting the HGMD database with the 1KG database, four disease-causing variants were identified in 9 individuals, all heterozygotes. This yields a carrier rate of 1 in 278 and an affected rate of 1 in 308,641. CONCLUSIONS: We estimate one in 308,641 is contraindicated with vitamin D supplement which will cause nephrolithiasis and nephrocalcinosis. Previous genetic analyses have characterized the prevalence of IIH using dbSNP which include both pathogenic and benign variants. We used HGMD to limit the variants that are disease-causing, and used 1KG to assess the frequencies in the general population. Further studies are needed to identify other contributing factors towards IIH, but this study provides an estimate of the clinical prevalence of IIH to identify patients for whom vitamin D supplementation is contraindicated. Source of Funding: © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e120 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Alicja Tomaszewski More articles by this author Cindy Lin More articles by this author Joshua Chang More articles by this author Katreya Lovrenert More articles by this author John Weaver More articles by this author Jessica Hannick More articles by this author Lynn Woo More articles by this author Chen-Han Wilfred Wu More articles by this author Expand All Advertisement PDF downloadLoading ...