NPC1 and Niemann-Pick disease type C: For example, saturation prime editing was used to classify 978 gene variants in NPC1; variants in NPC1 can cause Niemann-Pick disease type C.25To overcome the limits of prime editing efficiency, targeted haploidization of NPC1 was performed using Cas9 to eliminate all but one allele, therefore increasing the overall penetrance of prime edits at the NPC1 locus.