CRISPR-Based Correction of Monogenic Disease in Patient-Derived Induced Pluripotent Stem Cells

Abstract

Background: Isogenic pairs anchor monogenic disease modelling in induced pluripotent stem cells, and CRISPR correction has
made them routine across the monogenic disease spectrum.
Objective: To reassess where the residual risk in generating corrected isogenic pairs now lies, given that correction efficiency is no
longer the limiting obstacle.
Methods: Narrative review of gene editing studies, clone screening reports and early clinical applications.
Findings: Templated correction in human induced pluripotent stem cells ran at 1.0%, whereas prime editing reached 4.3-24.8% in
human embryonic stem cells. Large on-target lesions appeared in 33% of 27 edited clones and in up to 40% of edited clones, all
passing standard PCR and Sanger checks; copy-neutral loss of heterozygosity occurred in 7 of 648 clones.
Conclusions: The evidence supports treating on-target structural damage, not efficiency, as the main threat to isogenic validity; it
does not show that amplicon sequencing alone validates a corrected pair.