The symptoms of Hunter syndrome vary from person to person. While one individual may have mild symptoms, another can develop severe complications. The symptoms of this condition are not present when a child is born, but start to develop after the first year of life. If symptoms start to manifest early (between 2 and 4 years of age), they are generally more severe.

Some of the symptoms of Hunter syndrome are described below:

• One of the first symptoms to develop is often abdominal hernia, which occurs when an abdominal organ or adipose tissue starts to protrude through a weakness in the abdominal wall.
• Ear infections, a runny nose and a cold are other common initial symptoms.
• Symptoms become more noticeable as the amount of glycosaminoglycans (GAG) continues to accumulate in cells throughout the body.
• Children with the syndrome often share characteristic facial features which include a prominent forehead, a nose that is shallow-bridged and an enlarged tongue. The head and abdomen may also seem larger than usual.
• The continued accumulation of GAG in cells can eventually affect the function of important organs. The walls of the heart and heart valves thicken which can lead to a decline in cardiac function, for example. The bronchial walls also thicken which can lead to respiratory complications such as obstructive airway disease. Pulmonary involvement may also lead to a reduced lung capacity.
• As the liver and spleen gradually increase in size, the abdomen can become distended and cause hernias to become more obvious.
• Ivory-colored lesions may develop on the skin of the upper arms, back and legs.
• Major joints such as the elbows, shoulders, wrists, knees and hips may be become stiff, reducing the child’s range of motion and eventually making it difficult to walk. As the finger and thumb joints are involved, hand movements such as gripping an object may become more difficult.
• The accumulation of GAG in the brain can eventually lead to developmental delays and mental retardation. The extent to which function is lost varies between individuals.