Hunter Syndrome (or Mucopolysaccharidosis/MPS II) is a rare condition affecting between 1 in 100,000 to 1 in 150,000 male births.
Children with Hunter Syndrome are missing an enzyme called iduronate-2 sulfatase which is essential in cutting up the certain molecules (mucopolysaccharides or GAG) called dermatan sulfate and heparan sulfate. The incomplete broken down mucopolysaccharides remain stored in cells in the body causing progressive damage.
Physical effects from Hunter Syndrome begin at birth and include damage to organs, joints, and breathing difficulties. Many children continue to have frequent infections of the ears and respiratory tract. The continued storage of GAG in cells can lead to organs being affected in important ways. The thickening of the heart valves along with the walls of the heart can result in a progressive decline in cardiac function. The walls of the airway may become thickened as well, leading to breathing problems while sleeping (obstructive airway disease). Children with Hunter Syndrome often look alike and have a distinctive coarseness in their facial features, including a prominent forehead, a nose with a flattened bridge, and enlarged lips and tongue. They may also have a large head, short neck, broad chest, thick hands, and an enlarged abdomen.(Huntersyndromefoundation.org)