CYP24A1-mediated abnormal calcium handling' /> CYP24A1-mediated abnormal calcium handling' />
SFEBES2022 Oral Poster Presentations Bone and Calcium (4 abstracts)
1University of East Anglia, Norwich, United Kingdom; 2John Innes Centre, Norwich, United Kingdom; 3School of Biology, Norwich, United Kingdom; 4Clinical Biochemistry Norfolk and Norwich University Hospital, Norwich, United Kingdom
Hypomorphic CYP24A1 protein coding mutations causing inappropriate 1,25(OH)2D concentrations are associated with idiopathic infantile hypercalcemia and adult-onset hypercalciuria and nephrolithiasis. It is unclear why some cases present with CYP24A1-mediated abnormal calcium handling lack protein-coding CYP24A1 mutations. Non-coding region mutations, e.g. the 3 UTR, impacting messenger RNA (mRNA) structure have rarely been studied in patients. RNAs fold into complex structures critical for their function and regulation including post-transcriptional modifications, localisation, translation and degradation. Non-coding variants altering CYP24A1 mRNA structure may be the fundamental mechanism behind cases with absent protein coding pathogenic mutations. Biochemical profiling, next generation sequencing, bioinformatics, proteomic and molecular cytogenetic approaches were used to examine CYP24A1 in a patient cohort of four adults with hypercalciuria and nephrolithiasis and two infants with nephrocalcinosis. We identified inappropriate 1,25(OH)2D concentrations (mean±