Arginine codon 123 (CGG) in exon 3 was changed to tryptophan (TGG) (p.R123W) using an sgRNA (targeting CCGGATCCCAGCCGATGTGGATC) and an ssODN template with CRISPR/Cas9 technology. The mutation represents the same human mutation associated with hypertrophic cardiomyopathy (HCM). (J:342762)