LGR5 and isolated hemihyperplasia: Given the significant heart and liver editing, the importance of MPS-IH cardiac pathology, and the rationale that in utero editing can target progenitor cells, NGS editing efficiencies were evaluated in liver LGR5+ progenitor cells (~12.8%) and cardiac cell subpopulations including myocytes (~12.6%), endothelial cells (~3.0%), and fibroblasts (~2.3%) (Fig. 1d, e).