Sleep Disorders in Klinefelter Syndrome and Other Sex Chromosome Aneuploidies: A Narrative Review

Background: Sex chromosome aneuploidies (SCAs) are among the most frequent types of chromosomal aneuploidies and include Klinefelter syndrome (47,XXY and higher-grade variants), 47,XYY syndrome, Turner syndrome (45,X), and trisomy X (47,XXX). These conditions share complex neurodevelopmental, endocrine, and metabolic features with important implications for reproductive and general health. Sleep plays a pivotal role in neurocognitive functioning, mood regulation, cardiometabolic homeostasis, and hypothalamic–pituitary–gonadal axis activity, yet sleep disorders remain poorly characterized and under-recognized in SCAs. Methods: This narrative review synthesizes current evidence on sleep disturbances in SCAs, with particular emphasis on male phenotypes, while integrating evidence from female SCAs to highlight shared mechanisms and overlapping sleep phenotypes. Results: Available data indicate an increased prevalence of insomnia, sleep fragmentation, excessive daytime sleepiness, circadian rhythm disturbances, and sleep-disordered breathing from childhood through adulthood. In Klinefelter syndrome, sleep alterations appear multifactorial, arising from the interaction between hypogonadism, obesity, psychiatric vulnerability, neurocognitive deficits, and possible circadian and melatonin dysregulation. Evidence in 47,XYY and higher-grade male SCAs, although limited, suggests a predominant contribution of neurodevelopmental and behavioral factors. Emerging findings also implicate oxidative stress as a potential mechanistic link between sleep disruption, metabolic dysregulation, and neurocognitive impairment. Conclusions: Overall, the literature is fragmented and methodologically heterogeneous, underscoring the need for systematic sleep screening and integrated multidisciplinary management within andrological care pathways to improve long-term health and reproductive outcomes in individuals with SCAs.