We employed a reprogramming procedure using lentiviral delivery of four transcription factors: human OCT4, KLF4, SOX2, and cMYC (OKSM) (Chen et al., 2011) and observed greatly reduced reprograming efficiency of primary human fibroblasts derived from skin biopsies of AD-HIES patients compared to those from healthy control volunteers (Fig. 1). Here, KLF4 is linked to Alzheimer disease.