The hiPSC lines used were derived with support from the Joslin DRC iPS Core Facility ( NIH 5 P30 DK036836-27 ). FACS analysis was supported by the HSCI/DRC Flow Core (NIH P30DK036836 ). Microarray studies were performed by the Molecular Genetics Core Facility at Children's Hospital Boston, supported by NIH- P50-NS40828 and NIH- P30-HD18655 . We thank B. Wagner for assistance with microarray analyses; and K. Tomita, E.K. Tan, N.R. Dunn, Y.-H. Zhou, and Y.-I. Chi for providing plasmids. A.K.K.T. was supported by a Juvenile Diabetes Research Foundation (JDRF) Postdoctoral Fellowship and is currently supported by the Institute of Molecular and Cell Biology (IMCB), A∗STAR , NHG-KTPH SIG/14033 , the NUHS-CG Metabolic In-Vitro Core Seed Funding , and the JCO Career Development Award (CDA) 15302FG148 , A∗STAR. I.A.V. is supported by an HSCI Sternlicht Director's Fund Award and a NIH F31DK098931 award. E.D. is supported by an Advanced JDRF Postdoctoral Fellowship . H.R. is supported by grants from Bergen Forskningsstiftelse (BFS), the Western Norway Regional Health Authority and the Novo Nordisk Foundation . R.N.K. is supported by the HSCI , NIH grants RO1 DK 67536 , RO1 DK 055523 , and R01103215 , and a grant from AstraZeneca .