Derivation of integration‐free iPSCs from a Klinefelter syndrome patient

PURPOSE: Klinefelter syndrome (KS) (47, XXY) is the most common sex chromosome abnormality in humans. KS is characterized by gynecomastia, tall stature, small testes, low testosterone levels, learning disabilities, and behavioral problems. KS is also associated with infertility due to non‐obstructive azoospermia (NOA). The mechanism underlying NOA is still poorly understood, and although there is no current treatment, the use of microdissection testicular sperm extraction (micro‐TESE) followed by in vitro fertilization can result in successful conception. The generation of induced pluripotent stem (iPS) cells derived from KS patients may be useful for studying the disease mechanism and identifying novel therapies. METHODS: Cells from a KS patient were transduced with Sendai viral vectors encoding four transcription factors, OCT4, SOX2, KLF4, and C‐MYC, and the transduced cells were analyzed for in vitro and in vivo pluripotency. RESULTS: KS patient‐derived iPS cells were successfully generated and shown to produce teratomas in the testes of SCID mice. In vitro differentiation of the iPS cells into cardiomyocyte‐like cells was confirmed by the presence of clusters of beating cells. CONCLUSIONS: KS patient‐derived iPS cells that could differentiate into cardiomyocyte‐like cells were established.