Rapid Eye Movement (REM) Sleep Behaviour Disorder in Moebius Syndrome: A Rare Pediatric Case.

Moebius syndrome is a rare, non-progressive congenital disorder, most commonly characterized by impairment of the abducens (VI) and facial (VII) cranial nerves, resulting in facial palsy and limited ocular abduction. A broad spectrum of associated clinical manifestations includes craniofacial abnormalities, limb malformations, and neuromotor developmental delay. Sleep disorders are frequently reported in these patients, most often related to sleep-disordered breathing. In contrast, rapid eye movement (REM) sleep behavior disorder (RBD) is exceptionally rare, both in pediatric patients and in association with this syndrome. We report the case of a 13-year-old male diagnosed with Moebius syndrome in the neonatal period, who developed recurrent episodes of nocturnal agitation, vocalizations, and dream enactment behaviors. Polysomnography demonstrated structural alterations of REM sleep with reduced muscle atonia and abnormal motor activity, findings consistent with RBD. Despite the implementation of sleep hygiene measures and pharmacological therapy, clinical response was limited. This case underscores the importance of actively investigating sleep disturbances in Moebius syndrome, not only to address the more common sleep-related breathing disorders but also to recognize rare conditions, such as RBD, which may significantly impact quality of life. Given the scarcity of evidence on pediatric RBD, particularly in association with congenital neurological syndromes, further research is needed to improve diagnostic and therapeutic strategies.