Dataset Information
Molecular Analysis of CYP27B1 Mutations in Vitamin D-Dependent Rickets Type 1A: c.590G > A (p.G197D) Missense Mutation Causes a RNA Splicing Error.
Ontology highlight
ABSTRACT: Context
Vitamin D-dependent rickets type 1A (VDDR1A) is a rare autosomal recessively inherited disorder due to loss-of-function mutations in the CYP27B1 gene. CYP27B1 encodes an enzyme of 25-hydroxyvitamin D-1?-hydroxylase for converting inactive 25-OHD to biologically active 1,25-(OH)2D.Objective
To identify underlying genetic defects in patients with VDDR1A.Methods
Twelve patients from 7 Turkish and 2 Saudi families were investigated. The coding exons and intron-exon boundaries of the CYP27B1 gene were amplified by Polymerase Chain Reaction (PCR) from peripheral lymphocyte DNA. PCR products were directly sequenced. The consequences of c.590G > A mutation were analyzed by in silico and functional analysis.Results
CYP27B1 mutations were identified in all the patients. Two novel mutations were identified in two separate families: c.171delG (family 7) and c.398_400dupAAT (family 8). The intra-exon deletion of c.171delG resulted in a frameshift and premature stop codon 20 amino acids downstream from the mutation (p.L58Cfs?20). The intra-exon duplication of c.398_400dupAAT generated a premature stop codon at the mutation site (p.W134?). A missense c.590G > A (p.G197D) mutation was found in a patient from family 4 and caused a defect in pre-mRNA splicing. As a result, two populations of transcripts were detected: the majority of them with intron 3 retention (83%), and the minority (17%) being properly spliced transcripts with about 16% of wild-type enzymatic activity. The remaining nine patients from six families carried a previously reported c.1319_1325dupCCCACCC (F443Pfs?24) mutation. Clinically, all the patients need continued calcitriol treatment, which was consistent with inactivation of 25-hydroxy vitamin D1?-hydroxylase activity.Conclusion
Two novel frameshift CYP27B1 mutations were identified and predicted to inactivate 25-hydroxyvitamin D-1?-hydroxylase. The loss of enzymatic activity by c.590G > A missense mutation was mainly caused by aberrant pre-mRNA splicing.
SUBMITTER: Zou M
PROVIDER: S-EPMC7729158 | biostudies-literature | 2020
REPOSITORIES: biostudies-literature
Publications
Molecular Analysis of <i>CYP27B1</i> Mutations in Vitamin D-Dependent Rickets Type 1A: c.590G > A (p.G197D) Missense Mutation Causes a RNA Splicing Error.
Frontiers in genetics 20201127
<h4>Context</h4>Vitamin D-dependent rickets type 1A (VDDR1A) is a rare autosomal recessively inherited disorder due to loss-of-function mutations in the <i>CYP27B1</i> gene. <i>CYP27B1</i> encodes an enzyme of 25-hydroxyvitamin D-1α-hydroxylase for converting inactive 25-OHD to biologically active 1,25-(OH)<sub>2</sub>D.<h4>Objective</h4>To identify underlying genetic defects in patients with VDDR1A.<h4>Methods</h4>Twelve patients from 7 Turkish and 2 Saudi families were investigated. The coding ...[more]