Abstract
Cornelia de Lange syndrome (CdLS) is a rare genetic disorder that is characterized by specific facial, skeletal, and behavioral features associated with variable degrees of intellectual disabilities. Sleep disturbances have been reported in patients with CdLS including insomnia, sleep-disordered breathing, intrinsic sleep disorders, and circadian rhythm disorders. The prevalence of sleep-related breathing disorders, in particular, obstructive sleep apnea (OSA), was conducted using validated questionnaires. We report the first case of CdLS that confirmed a moderate to severe degree of OSA using overnight polysomnography, which is the gold standard diagnostic test for OSA.