fa پژوهشي اصیل Original Research We present the case of a 7-year-old boy with a history of aggressive behavior, speech delay and progressive neurodevelopmental regression. Mucopolysaccharidosis was suspected based on skeletal and behavioral symptoms and confirmed by whole exome sequencing. 29 31 http://ijca.iums.ac.ir/browse.php?a_code=A-10-1-65&slc_lang=fa&sid=1 Ladan Afsharkhas 1003194753284600653 1003194753284600653 No Ali‐Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran. Parvaneh Karimzadeh 1003194753284600654 1003194753284600654 No Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Fatemeh Hajizadeh Saffar fhsaffar@gmail.com 1003194753284600655 1003194753284600655 Yes Ali‐Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran. Nasim Sajadi 1003194753284600656 1003194753284600656 No Ali‐Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran Hossein Ghaemi 1003194753284600657 1003194753284600657 No Ali‐Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran.