design: Targeted amplicon sequencing to quantify CRISPR/Cas9 genome editing outcomes in K562 human cells. Cells were electroporated with Cas9 RNPs and harvested 48 h post-editing. Genomic regions spanning the sgRNA target site X_48791327_48791347_-_1st_rep (target sequence: GCCACTCAATGGAGTTACCTGGG) were amplified using a two-step PCR Illumina amplicon library preparation.