Schaaf-Yang Syndrome Presenting with Prolonged Hyperthermia in a Child: A Case Report

Introduction: Schaaf-Yang syndrome (SYS) is a rare autosomal dominant disorder, first identified in 2013, resulting from mutations in the paternal allele of the MAGEL2 gene. Schaaf-Yang syndrome exhibits clinical features similar to those of Prader-Willi syndrome (PWS), including hypotonia, joint contractures, developmental delay, and intellectual disability. However, SYS is also characterized by unique manifestations, such as recurrent hyperthermia, feeding difficulties, respiratory distress, and seizures. This case report describes the first SYS case identified in Iran. Case Presentation: A one-year-old female, born to consanguineous parents, presented with recurrent episodes of hyperthermia, respiratory distress, and seizures since the neonatal period. Despite initial empirical treatment with broad-spectrum antibiotics for suspected infections, her symptoms persisted. Physical examination revealed hypotonia, camptodactyly, and hand contractures. Genetic testing confirmed SYS with a MAGEL2 gene mutation (c.1923dupC, p.V643Gfs*70) and probable pathogenic variants in ASPM and KIF7. The hyperthermia was attributed to hypothalamic dysfunction, a hallmark of SYS, rather than an infectious cause. The patient remains under follow-up without specific pharmacological intervention. Conclusions: This case emphasizes the importance of considering SYS in patients presenting with unexplained fever, seizures, and neurodevelopmental delays. Early genetic testing is crucial for diagnosing SYS and differentiating it from conditions such as PWS or infection-related disorders. Timely diagnosis can improve management strategies and help reduce the risk of lasting neurological impairments associated with this genetic disorder.