Abstract
Klinefelter Syndrome (KS) is caused by the presence of a supernumerary X chromosome. Cytogenetic studies revaled that 80-90% of patients carry a 47-XXY karyotype, while 10-20% of cases are represented by mosaic 46-XY/47-XXY and high-grade aneuploidies 48-XXXY and 48-XXYY. The phenotypic traits of KS are highly variable across individuals and include cognitive dysfunction, metabolic dysregulation, osteoporosis, and cardiovascular diseases. Here, we describe the derivation of multiple 47-XXY iPSC lines from three unrelated KS patients to study the impact of supernumerary X chromosome during early development.