CRISPR/Cas9 genome editing is used to insert the following construct into the endogenous locus: chicken actin splice donor, rabbit beta-globin splice acceptor, a loxP site, a STOP cassette (3 repeats of SV40 polyA termination signal), a loxP site, and full length human NGLY1, N-glycanase 1, under the control of the CAG promoter. (J:101977)