Dosage Counts: Correcting Trisomy-21-Related Phenotypes in Human Organoids and Xenografts.

Studies in mice suggest that Olig2 gene dosage alters cerebral cortical interneuron development and contributes to trisomy-21/Down-syndrome-related intellectual disability. Xu et al. (2019) extend these studies through the remarkable use of cerebral organoid and human iPSC/mouse brain chimera experimental systems that provide an opportunity for the development of novel therapeutics.