Hypermethylation of the MKRN3 DMR is a frequent event in iPSCs and escapes control by the PWS-IC. (A) Summary table of the features of the five established iPSC lines used. (B) PWS-IC and MKRN3 DMR COBRA in the five iPSC lines (and also in Ctrl FIBs for MKRN3 DMR). White circle, unmethylated band; half black circle, partially methylated band; black circle, fully methylated band. (C) Scheme of the expected and the observed epigenetic and transcriptional profile of the human chr15q11-q13 region in Ctrl and AS iPSC lines. Blue rectangles, imprinted genes expressed from the paternal allele; red rectangles, imprinted genes expressed from the maternal allele; gray rectangles, silenced imprinted genes; white lollipops, unmethylated DNA; black lollipops, methylated DNA; Pat, paternal allele; Mat, maternal allele; green arrowheads highlight the epigenetic errors found; iPSCs lines in black correspond to the lines generated in this study; iPSCs in red correspond to the previously published IPSC lines.