LONDON – The mutation introduced into the germline of the world's first CRISPR gene-edited babies is associated with a 21% increase in mortality in later life, according to a new study. Chinese scientist Jiankui He made the edits to the CCR5 chemokine receptor gene in human embryos with the aim of mimicking the effect of the naturally occurring delta32 mutation, which protects against HIV infection in Europeans. The birth of twin girls carrying the CRISPR edit was announced in November last year. But now an analysis based on genomic data and death register information of 409,693 of the volunteers in the UK Biobank has found that people who are homozygous for the delta32 mutation have a significantly higher death rate between the ages of 41 and 78, than people with one or no copies of the mutation.