Figure 1

HD-iPSCs, corrected iPSCs, and iPSC-derived neurons reveal key disease-associated phenotypes. An et al. [3] and the HD iPSC Consortium [2] generated HD-iPSC lines. An et al. [3] also generated corrected HD-iPSCs by homologous recombination and showed that, when compared to corrected HD-iPSCs, HD-iPSCs have increased expression of genes that are induced by the TGF-β signaling pathway and decreased expression of cadherin pathway genes [3]. HD-iPSC lines developed by the HD iPSC Consortium were further differentiated to form NPCs and DARPP-32-positive striatal-like neurons [2]. These NPCs yielded evidence for the altered expression in HD of genes that are involved in cell signaling, cell cycling, axon guidance, and neurodevelopmental pathways. As delineated here, future studies might compare these two datasets and thus could evaluate the expression of the target genes of those transcription factors known to interact with huntingtin, examine mitochondrial dysfunction in HD and investigate the exact identity of the dying cells in HD. NPC, neural progenitor cell; ROS, reactive oxygen species; TF, transcription factor.