Israeli researchers have created cell lines, using cells donated by an individual with Klinefelter syndrome, that had different combinations of sex chromosomes but were otherwise isogenic. As reported in Stem Cell Reports on Nov. 24, 2022, lead investigator Benjamin Reubinoff, a clinician and professor in obstetrics and gynecology at Hadassah Hebrew University in Jerusalem, and team used cells donated from a mosaic Klinefelter syndrome patient to create the cell-based model. Patients with Klinefelter syndrome appear male, but have an extra X chromosome.