Induced pluripotent stem cells (iPSC) lines were derived from these patient samples using an excisable floxed polycistronic hSTEMCCA lentiviral vector. Short tandem repeat (STR)-based DNA fingerprinting was used to confirm iPSC identity, as a match to original patient or control donor. Additional genotyping was performed using Illumina Omni5 SNP arrays; these data are available in dbGAP (http://www.ncbi.nlm.nih.gov/gap). The iPSCs were then driven toward a glial progenitor cell (GPC) fate using previously described protocols (Wang et al., 2013). Cells were harvested between 160–240 DIV, by which time most typically expressed the bipotential GPC marker PDGFαR/CD140a, while the remainder were A2B5+/CD140a− astrocytes. The karyotypes of all iPSC lines were assessed during glial differentiation to ensure genotypic stability of the cells utilized in all experiments presented here (karyotyping by WiCell, Madison, WI). All iPSCs showed a normal karyotype, except for line 51, which was found to have a balanced Robertsonian translocation of chromosome 13, an anomaly previously associated with juvenile-onset schizophrenia (Graw et al., 2012).
