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Journal article

Envisioning the development of a CRISPR-Cas mediated base editing strategy for a patient with a novel pathogenic CRB1 single nucleotide variant

Abstract:

Background
Inherited retinal degeneration (IRD) associated with mutations in the Crumbs homolog 1 (CRB1) gene is associated with a severe, early-onset retinal degeneration for which no therapy currently exists. Base editing, with its capability to precisely catalyse permanent nucleobase conversion in a programmable manner, represents a novel therapeutic approach to targeting this autosomal recessive IRD, for which a gene supplementation is challenging due to the need to target three different retinal CRB1 isoforms.

Purpose
To report and classify a novel CRB1 variant and envision a possible therapeutic approach in form of base editing.

Methods
Case report.

Results
A 16-year-old male patient with a clinical diagnosis of early-onset retinitis pigmentosa (RP) and characteristic clinical findings of retinal thickening and coarse lamination was seen at the Oxford Eye Hospital. He was found to be compound heterozygous for two CRB1 variants: a novel pathogenic nonsense variant in exon 9, c.2885T>A (p.Leu962Ter), and a likely pathogenic missense change in exon 6, c.2056C>T (p.Arg686Cys). While a base editing strategy for c.2885T>A would encompass a CRISPR-pass mediated “read-through” of the premature stop codon, the resulting missense changes were predicted to be “possibly damaging” in in-silico analysis. On the other hand, the transversion missense change, c.2056C>T, is amenable to transition editing with an adenine base editor (ABE) fused to a SaCas9-KKH with a negligible chance of bystander edits due to an absence of additional Adenines (As) in the editing window.

Conclusions
This case report records a novel pathogenic nonsense variant in CRB1 and gives an example of thinking about a base editing strategy for a patient compound heterozygous for CRB1 variants.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1080/13816810.2022.2073599

Authors

More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Clinical Neurosciences
Oxford college:
St Cross College
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Clinical Neurosciences
Role:
Author
ORCID:
0000-0002-2941-4464
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Clinical Neurosciences
Role:
Author
ORCID:
0000-0001-7459-1024


Publisher:
Taylor and Francis
Journal:
Ophthalmic Genetics More from this journal
Volume:
43
Issue:
5
Pages:
661-670
Publication date:
2022-05-10
Acceptance date:
2023-04-30
DOI:
EISSN:
1744-5094
ISSN:
1381-6810
Pmid:
35538629


Language:
English
Keywords:
Pubs id:
1259571
Local pid:
pubs:1259571
Deposit date:
2023-05-26
ARK identifier:

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