A Clinical Practice Example of Smith–Magenis Syndrome in the Neuropediatric Clinic: Etiology, Clinical Presentation, Diagnostics and Therapeutic Approaches—A Case Report

Background/Objectives: Smith–Magenis syndrome (SMS) is a rare neurogenetic disorder caused by a microdeletion in chromosome region 17p11.2 or by pathogenic variants in the RAI1 gene. The syndrome is characterized by a distinctive neurobehavioral profile, including cognitive deficits, sleep disturbances, self-injurious behavior, and typical dysmorphic features. A characteristic diagnostic hallmark is paradoxical melatonin secretion, with increased daytime levels instead of the normal nocturnal peak. This article aims to summarize current knowledge on the etiology, diagnostics, EEG findings, therapy, and prognosis of SMS from a neuropediatric perspective. Methods: A narrative review of the literature on Smith–Magenis syndrome was conducted, focusing on genetic background, clinical features, diagnostic approaches, EEG characteristics, therapeutic strategies, and prognosis. In addition, a detailed clinical case of a 16-year-old female patient with SMS is presented. Results: The reviewed data confirm that SMS is associated with characteristic neurobehavioral abnormalities and sleep–wake rhythm disturbances. EEG findings may include epileptiform activity without overt epilepsy. In the presented case, “Rolandic-type” spike–sharp wave complexes were observed on EEG and are interpreted as an expression of congenital disturbances in brain maturation processes. Therapeutic recommendations addressing behavioral symptoms and sleep regulation are discussed. Conclusions: Smith–Magenis syndrome represents a complex neurodevelopmental disorder with distinctive clinical, neurophysiological, and genetic features. Early recognition of characteristic signs, including sleep disturbances and EEG abnormalities, is essential for appropriate management. A multidisciplinary, individualized therapeutic approach may improve quality of life and long-term outcomes.