PROS1 and teratoma: Although previous studies have reported that the deficiency of functional DNA repair proteins may hinder somatic cell reprogramming and teratoma formation in vivo (i.e., WRN (Shimamoto et al., 2014; Wang et al., 2018c), p53 (Kawamura et al., 2009), and Fanconi genes (Muller et al., 2012)), we did not observe any defects in the derivation or pluripotency of CS patient-specific iPSC lines.