A putative frameshift variant in the CHM gene is associated with an unexpected splicing alteration in a choroideremia patient.
Journal
Molecular genetics & genomic medicine
ISSN: 2324-9269
Titre abrégé: Mol Genet Genomic Med
Pays: United States
ID NLM: 101603758
Informations de publication
Date de publication:
11 2020
11 2020
Historique:
received:
13
05
2020
revised:
29
07
2020
accepted:
10
08
2020
pubmed:
20
9
2020
medline:
8
6
2021
entrez:
19
9
2020
Statut:
ppublish
Résumé
Due to the limited availability of mRNA analysis data, the number of exonic variants resulting in splicing impairment is underestimated although aberrant splicing correction is a promising therapeutic option to treat monogenic diseases, including choroideremia (CHM), a rare X-linked eye disorder arising from sequence alteration of the CHM gene. Herein we report an exonic frameshift variant associated with an mRNA splicing alteration that leads to a CHM hypomorphic allele. Total RNA and genomic DNA were extracted from peripheral blood of a patient affected by a mild form of CHM. The CHM gene was analyzed by PCR-based methods and Sanger sequencing. Besides the known c.1335dup frameshift variant, mRNA analysis revealed a splicing alteration that restored the reading frame of the mutant transcript, likely leading to an aberrant protein with residual activity. Bioinformatic analyses identified novel putative exonic splicing enhancer elements and provided clues that also pre-mRNA secondary structure should be taken into account when exploring splicing mechanisms. A careful molecular characterization of the c.1335dup variant's effect explains the relationship between genotype and phenotype severity in a CHM patient and provides new perspectives for the study of therapeutic strategies based on splicing correction in human diseases.
Sections du résumé
BACKGROUND
Due to the limited availability of mRNA analysis data, the number of exonic variants resulting in splicing impairment is underestimated although aberrant splicing correction is a promising therapeutic option to treat monogenic diseases, including choroideremia (CHM), a rare X-linked eye disorder arising from sequence alteration of the CHM gene. Herein we report an exonic frameshift variant associated with an mRNA splicing alteration that leads to a CHM hypomorphic allele.
METHODS
Total RNA and genomic DNA were extracted from peripheral blood of a patient affected by a mild form of CHM. The CHM gene was analyzed by PCR-based methods and Sanger sequencing.
RESULTS
Besides the known c.1335dup frameshift variant, mRNA analysis revealed a splicing alteration that restored the reading frame of the mutant transcript, likely leading to an aberrant protein with residual activity. Bioinformatic analyses identified novel putative exonic splicing enhancer elements and provided clues that also pre-mRNA secondary structure should be taken into account when exploring splicing mechanisms.
CONCLUSION
A careful molecular characterization of the c.1335dup variant's effect explains the relationship between genotype and phenotype severity in a CHM patient and provides new perspectives for the study of therapeutic strategies based on splicing correction in human diseases.
Identifiants
pubmed: 32949230
doi: 10.1002/mgg3.1490
pmc: PMC7667377
doi:
Substances chimiques
Adaptor Proteins, Signal Transducing
0
CHM protein, human
0
RNA, Messenger
0
Types de publication
Case Reports
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
e1490Informations de copyright
© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.
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