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What is CRISPR/Cas9?
  1. Melody Redman1,
  2. Andrew King2,
  3. Caroline Watson3,
  4. David King4
  1. 1HYMS Centre for Education Development (CED), Hull York Medical School, University of York, York, UK
  2. 2Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
  3. 3Department of Haematology, Oxford University NHS Foundation Trust, Churchill Hospital, Oxford, UK
  4. 4Academic Unit of Child Health, Sheffield Children's Hospital, Sheffield, UK
  1. Correspondence to Dr David King, Academic Unit of Child Health, Sheffield Children's Hospital, Western Bank, Sheffield S10 2TH, UK; d.a.king{at}

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Clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 is a gene-editing technology causing a major upheaval in biomedical research. It makes it possible to correct errors in the genome and turn on or off genes in cells and organisms quickly, cheaply and with relative ease. It has a number of laboratory applications including rapid generation of cellular and animal models, functional genomic screens and live imaging of the cellular genome.1 It has already been demonstrated that it can be used to repair defective DNA in mice curing them of genetic disorders,2 and it has been reported that human embryos can be similarly modified.3 Other potential clinical applications include gene therapy, treating infectious diseases such as HIV and engineering autologous patient material to treat cancer and other diseases. In this review we will give an overview of CRISPR/Cas9 with an emphasis on how it may impact on the specialty of paediatrics. Although it is likely to have a significant effect on paediatrics through its impact in the laboratory, here we will concentrate on its potential clinical applications. We will also describe some of the difficulties and ethical controversies associated with this novel technology.

Overview of CRISPR/Cas9

CRISPR/Cas9 is a gene-editing technology which involves two essential components: a guide RNA to match a desired target gene, and Cas9 (CRISPR-associated protein 9)—an endonuclease which causes a double-stranded DNA break, allowing modifications to the genome (see figure 1).

Figure 1

The CRISPR/Cas9 system.1 Clustered regularly interspaced palindromic repeats (CRISPR) refers to sequences in the bacterial genome. They afford protection against invading viruses, when combined with a series of CRISPR-associated (Cas) proteins. Cas9, one of the associated proteins, is an endonuclease that cuts both strands of DNA. Cas9 is directed to its target by a section of RNA. This can be synthesised as a single strand called …

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  • Contributors DK conceived the idea for this article. All authors were involved in writing and reviewing the final manuscript.

  • Funding AK is supported by a Wellcome Trust Fellowship (108785/Z/15/Z).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.