Blood samples were obtained from six subjects harboring previously identified ATM mutations (Figure 1A): two from subjects diagnosed with A-T (labeled as “Q”) and four from carrier parents (labeled as “CAR”). iPSC were prepared from four of these subjects (asterisks in Figure 1A) using enriched, activated T cells and non-integrating Sendai viral vectors to deliver reprogramming factors (Moore et al., 2012). Sample iPSC colonies from each subject had standard morphology and stained positive for Oct4 and TRA-1-60, as shown in Figure 1B. For each subject, several sublines were picked from single colonies, expanded, and stored as frozen stocks. A subset of these was tested for gene expression patterns consistent with pluripotency. As shown in Figure 1C, three iPSC sublines (Q1SA, Q3SA, and Q3SC) all clustered with unrelated iPSC prepared from a non-A-T subject (“iPSC”), but they clustered separately from H1 human embryonic stem cell (hESC)-derived neural stem cells (NSC) at day 0 (NSC0) or NSC following 5 days of differentiation (NSC5) (Sauvageau et al., 2013), as well as dopaminergic neurons (DAN) differentiated from iPSC using the dual-SMAD protocol (Kriks et
