Kabuki syndrome (KS) is a rare epigenetic disorder caused by heterozygous loss of function variants in either KMT2D (90%) or KDM6A (10%), both involved in regulation of histone methylation. While sleep disturbance in other Mendelian disorders of the epigenetic machinery has been reported, no study has been conducted on sleep in KS. This study assessed sleep in 59 participants with KS using a validated sleep questionnaire. Participants ranged in age from 4 to 43 years old with 86% of participants having a pathogenic variant in KMT2D. In addition, data on adaptive function, behavior, anxiety, and quality of life were collected using their respective questionnaires. Some form of sleep issue was present in 71% of participants, with night-waking, daytime sleepiness, and sleep onset delay being the most prevalent. Sleep dysfunction was positively correlated with maladaptive behaviors, anxiety levels, and decreasing quality of life. Sleep issues were not correlated with adaptive function. This study establishes sleep disturbance as a common feature of KS. Quantitative sleep measures may be a useful outcome measure for clinical trials in KS. Further, clinicians caring for those with KS should consider sleep dysfunction as an important feature that impacts overall health and well being in these patients.
Keywords: KDM6A; KMT2D; MLL2; epigenetics; neurodevelopmental.
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