APOE and early-onset autosomal dominant Alzheimer disease: Along similar lines, Robin Lovell-Badge has pointed out, for example, that one of the applications of CRISPR in the context of embryo editing could be to delete the allele APOE4, which is the allele of the apolipoprotein E associated with Alzheimer's disease (with heterozygotes being approximately three-times and homozygotes 15-times more likely to develop the disease than homozygotes).