Chemical surgery to fix faulty genes
Scientists in China have revealed details of a new gene modifying technique called ‘chemical surgery’ or base editing, using the method to fix a genetic mutation responsible for the serious blood disorder beta-thalassaemia in human embryos.
Published in the journal Protein and Cell, the procedure uses similar molecules to the gene editing system CRISPR, but only alters one specific ‘letter’ or base in DNA, rather than repairing, removing or replacing longer stretches of sequence.
Many patients with beta-thalassaemia have a single letter mutation in a particular gene, and the Chinese team used this particular change as a model to test the efficiency of their method.
In total, around a fifth of the embryos had a successful edit, fixing the mutation in at least some of the cells. Although the embryos were not allowed to develop longer than a few days, this would in theory be enough to provide some improvement in the disease.
However, the team also found that in some cases they had managed to introduce new mutations into the gene, rather than fixing it - so clearly more work needs to be done on accuracy and efficiency.