Moreover, as more than 180 FSHD associated SMCHD1 variants have been described so far (Lemmers et al., 2019), a strategy based on CRISPR-Cas9 genome editing of a mutated SMCHD1 gene seems difficult to envisage in a near future. This evidence concerns the gene SMCHD1 and facioscapulohumeral muscular dystrophy.