ASPA and leukodystrophy: To test whether rAAV infection of NHP zygotes can deliver CRISPR to realize genome editing, we chose to target the ASPA gene, mutations of which cause a fatal pediatric leukodystrophy called Canavan disease.3 We designed three sgRNAs targeting a coding region in cynomolgus monkey ASPA exon 2 that is downstream of the start codon (sgASPA) (Figure1a).