X chromosome inactivation skewing is common in advanced carotid atherosclerotic lesions in females and predicts secondary peripheral artery events.

Sex-differences have been observed in the development of atherosclerosis between men and women. Women tend to have more stable and fibrous plaques compared to men. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men, were associated with cardiovascular health. In women, despite X-linked mechanisms like X chromosome inactivation (XCI) skewing was identified in various tissues. However, its relationship with atherosclerosis has not yet been investigated. In our study, we explored if prevalence of XCI skewing in advanced atherosclerotic lesions related to cardiovascular risk factors, histological plaque data, and clinical information. We found that XCI skewing was present in approximately 50% of human plaques, particularly those with plaque hemorrhage. Interestingly, we did not find any notable relationship between plaque skewing and clinical risk factors. However, we found that XCI was more present in women with peripheral artery events during the 3 years period following carotid endarterectomy. In summary, our findings indicate that XCI skewing is commonly observed in carotid plaques among females and may serve as a predictive factor for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.