3’ untranslated region structural elements in CYP24A1 are associated with infantile hypercalcaemia type 1

Ball, Nicole, Duncan, Susan, Zhang, Yueying, Payet, Rocky, Piec, Isabelle ORCID: https://orcid.org/0000-0002-0648-1330, Whittle, Eloise, Tang, Jonathan C. Y. ORCID: https://orcid.org/0000-0001-6305-6333, Schoenmakers, Inez, Lopez, Berenice, Chipchase, Allison, Kumar, Arun, Perry, Leslie, Maxwell, Heather, Ding, Yiliang, Fraser, William D. and Green, Darrell ORCID: https://orcid.org/0000-0002-0217-3322 (2023) 3’ untranslated region structural elements in CYP24A1 are associated with infantile hypercalcaemia type 1. Journal of Bone and Mineral Research, 38 (3). pp. 414-426. ISSN 0884-0431

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Abstract

Loss-of-function mutations in the CYP24A1 protein-coding region causing reduced 25OHD and 1,25(OH)2D catabolism have been observed in some cases of Infantile hypercalcaemia type 1 (HCINF1), which can manifest as nephrocalcinosis, hypercalcaemia and adult-onset hypercalciuria and renal stone formation. Some cases present with apparent CYP24A1 phenotypes but do not exhibit pathogenic mutations. Here, we assessed the molecular mechanisms driving apparent HCINF1 where there was a lack of CYP24A1 mutation. We obtained blood samples from 47 patients with either a single abnormality of no obvious cause or a combination of hypercalcemia, hypercalciuria and nephrolithiasis as part of our metabolic and stone clinics. We used liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine serum vitamin D metabolites and direct sequencing to confirm CYP24A1 genotype. Six patients presented with profiles characteristic of altered CYP24A1 function but lacked protein-coding mutations in CYP24A1. Analysis up- and downstream of the coding sequence showed single nucleotide variants (SNVs) in the CYP24A1 3’ untranslated region (UTR). Bioinformatics approaches revealed that these 3’ UTR abnormalities did not result in microRNA silencing but altered the CYP24A1 messenger RNA (mRNA) secondary structure, which negatively impacted translation. Our experiments showed that mRNA misfolding driven by these 3’ UTR sequence-dependent structural elements was associated with normal 25OHD but abnormal 1,25(OH)2D catabolism. Using CRISPR-Cas9, we developed an in vitro mutant model for future CYP24A1 studies. Our results form a basis for future studies investigating structure-function relationships and novel CYP24A1 mutations producing a semi-functional protein.

Item Type: Article
Additional Information: Author Acknowledgements: The Michael Davie Research Foundation and Norwich Medical School PhD Programme funded this study. EW is funded by the Bone Cancer Research Trust. WDF and DG are supported by The Difference Campaign. We thank the John Innes Centre bioimaging facility and staff for their contribution to this work and we thank Matthew Jefferson, Yingxue (Sophia) Wang and Gabriella Oliver-Wilkins for technical support. We are indebted to the patients for their participation in this study.
Uncontrolled Keywords: 3′ utr,bone,cyp24a1,renal,vitamin d,mrna,endocrinology, diabetes and metabolism,orthopedics and sports medicine ,/dk/atira/pure/subjectarea/asjc/2700/2712
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Faculty of Science > School of Biological Sciences
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Groups > Musculoskeletal Medicine
Faculty of Medicine and Health Sciences > Research Groups > Nutrition and Preventive Medicine
Faculty of Medicine and Health Sciences > Research Centres > Metabolic Health
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Depositing User: LivePure Connector
Date Deposited: 09 Jan 2023 13:32
Last Modified: 09 Mar 2024 01:47
URI: https://ueaeprints.uea.ac.uk/id/eprint/90481
DOI: 10.1002/jbmr.4769

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