Rapid-onset Obesity with Hypothalamic Dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) Syndrome: A Case Report Bahador Bagheri,1 Elham Pourbakhtyaran,2 Fateme Talebi Kiasari,3 Bahar Taherkhanchi,4 Sara Salarian,5,* and Afsaneh Sadeghi5 Introduction: Rapid-onset obesity with hypoventilation, hypothalamic dysfunction, and autonomic dysregulation (ROHHAD) is a rare disease. To date, there have been only few reported cases of valproate-induced ROHHAD syndrome. Case Presentation: We report a 5-year-old- Iranian girl who had normal growth and development until her 4th year of life. At that time, the patient developed weight gain, constipation, coldness in the extremities, and hyperhidrosis. She first presented to our children’s hospital with a suspected mediastinal mass on chest radiography. After surgery and resection of the mass (a ganglioneuroblastoma), extubation was unsuccessful, with tachycardia and hypertension occurring after each attempt. After 48 days in the ICU, we were still unable to wean her from mechanical ventilation. Finally, based on the rapid weight gain, hypoventilation, hypothalamic dysfunction, and signs of autonomic dysregulation, the patient was diagnosed with ROHHAD syndrome. Conclusions: Only a few case reports have described ROHHAD syndrome, and it is therefore difficult to manage. In children with rapid and earlyonset obesity associated with hypothalamic-pituitary endocrine dysfunction, ROHHADsyndrome should be considered in the differential diagnosis. Keywords: ROHHAD, Iran, Obesity Signs and Symptoms: Dramatic weight gain over a six- to twelve-month period Hypothalamic dysfunction such as inability to maintain normal water balance in the body;hypothyroidism; early or late puberty; growth hormone deficiency; and/or high prolactin levels Autonomic Dysregulation such as inability to regulate body temperature, slow heartbeat, excessive sweating, altered pupil response to light, strabismus (crossed eyes), and/or intestinal abnormalities Alveolar Hypoventilation with very shallow breathing during sleep Mild to severe behavioral problems may also be present. Affected children are also at an increased risk for certain types of tumors including ganglioneuromas and ganglioneuroblastomas. Laboratory tests Values Na 125mEq/L Blood glucose 85mg/dL Total cholesterol 176mg/dL Triglyceride 104mg/dL TSH 0.38µIU/mL T4 0.8ng/dL 1CancerResearchCenterandDepartmentof Pharmacology,SemnanUniversityof MedicalSciences,Semnan,IRIran 2Departmentof Pediatrics,MofidChildrenHospital,ShahidBeheshtiUniversityof MedicalSciences,Tehran,IRIran 3StudentResearchCenter,Schoolof Medicine,SemnanUniversityof MedicalSciences,Semnan,IRIran 4Departmentof Pediatrics,Schoolof Medicine,SemnanUniversityof MedicalSciences,Semnan,IRIran 5Departmentof Anesthesiology,MofidChildrenHospital,ShahidBeheshtiUniversityof MedicalSciences, Tehran, IRIran *Correspondingauthor: SaraSalarian,Department of Anesthesiology ,Mofid,ChildrenHospital, Shahid Beheshti University of Medical Sciences,Tehran,Iran. Tel: +98-2122227021,Fax: +98-2122220254,E-mail: Sarasalarian@yahoo.co