TCF4 and Pitt-Hopkins syndrome: Finally, we observed TCF4 upregulation in either of two iPSC lines derived from individuals with Pitt-Hopkins syndrome, following viral delivery of either the TSS-targeting (1.6-fold, q = 8e-5; 1.5-fold; q = 2e-7) or enhancer-targeting (1.2-fold, q = 3e-4; 1.1-fold; q = 0.02) gRNA (Fig. 5m-n).