In a pathbreaking proof of concept experimental study, MYBPC3 gene mutation causing hypertrophic cardiomyopathy has been corrected in human embryos using CRISPR-Cas9 gene editing technique. Study published in Nature  from Oregon Health & Science University, Portland, USA showed successful repair of the defective gene by cutting off the mutant sequence using CRISPR–Cas9. Embryos which were heterozygous for the mutation repaired the DNA break using the normal copy from the other parent. There were no off target mutations induced in the process. As always, ethical issues have to be addressed on whether heritable germ line editing can be used to prevent diseases, though editing of somatic cells for treatment of a disease may not raise much of ethical issues. Moreover, this is only a proof of concept experimental study. Successful translation to regular offspring devoid of the pathogenic mutation as well as no new off target mutation is still a long way off.
- Hong Ma et al. Correction of a pathogenic gene mutation in human embryos. Nature. 2017; 548, 413–419.