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 7_66995349_66995369_-_1st_rep (target sequence: GTGGTACGGATGAAGCGTGCCGG) were amplified using a two-step PCR Illumina amplicon library preparation.