A transcriptomic signature of X chromosome overdosage in Saudi Klinefelter syndrome induced pluripotent stem cells

Objective: The transcriptional landscape of Klinefelter syndromeduring early embryogenesis remains elusive. This study aimed to evaluate the impact of X chromosome overdosage in 47,XXY males induced pluripotent stem cells (iPSCs) obtained from patients with different genomic backgrounds and ethnicities. Design and method We derived and characterized 15 iPSC lines from four Saudi 47,XXY KS patients and one Saudi 46,XY male. We performed a comparative transcriptional analysis using the Saudi KS-iPSCs and a cohort of European and North American KS-iPSCs. Results: We identified a panel of X-linked and autosomal genes commonly dysregulated in Saudi and European/North American KS-iPSCs vs 46,XY controls. Our findings demonstrate that seven PAR1 and nine non-PAR escape genes are consistently dysregulated and mostly display comparable transcriptional levels in both groups. Finally, we focused on genes commonly dysregulated in both iPSC cohorts and identified several gene-ontology categories highly relevant to KS physiopathology, including aberrant cardiac muscle contractility, skeletal muscle defects, abnormal synaptic transmission, and behavioral alterations. Conclusions: Our results indicate that a transcriptomic signature of X chromosome overdosage in KS is potentially attributable to a subset of X-linked genes sensitive to sex chromosome dosage and escaping X inactivation, regardless of the geographical area of origin, ethnicity, and genetic makeup.