A 2 year-old boy is brought to the clinic with his mother for frequent upper respiratory infections for the last 3 months. General examination shows large head with prominent forehead and enlarged abdomen. On abdominal examination there is hepatosplenomegaly. The rest of examination is normal. After lab tests, the boy is diagnosed with Hunter syndrome. What is the mode of inheritance of this syndrome? http://medical-usmle.com/?p=951
