Hunter syndrome, or mucopolysaccharidosis II (MPS II), is a serious genetic disorder that primarily affects males. It interferes with the body’s ability to break down and recycle specific mucopolysaccharides (mew-ko-pol-ee-sak-ah-rides), also known as glycosaminoglycans (gli-ko-sah-mee-no-gli-cans) or GAG. Hunter syndrome is one of several related lysosomal storage diseases.
In Hunter Syndrome, GAG build up in cells throughout the body due to a deficiency or absence of the enzyme iduronate-2-sulfatase (I2S). This buildup interferes with the way certain cells and organs in the body function and leads to a number of serious symptoms. As the buildup of GAG continues throughout the cells of the body, signs of Hunters Syndrome become more visible. Physical manifestations for some people with Hunter syndrome include distinct facial features, a large head, and an enlarged abdomen. People with Hunter syndrome may also experience hearing loss, thickening of the heart valves leading to a decline in cardiac function, obstructive airway disease, sleep apnea, and enlargement of the liver and spleen. Range of motion and mobility may also be affected. In some cases of Hunter syndrome, central nervous system involvement leads to developmental delays and nervous system problems. Not all people with Hunter syndrome are affected by the disease in exactly the same way, and the rate of symptom progression varies widely. However, Hunter syndrome is always progressive and life-limiting.
Currently there is an intravenous enzyme replacement therapy that Jack receives weekly. Elaprase, the drug, is manufactured by Shire Genetic Therapies. http://www.shire.com/shireplc/en/home Unfortunately this drug does not cross the blood brain barrier, meaning its molecular make up is too large to get into the brain. So the weekly drug administered is not preventing the brain progression from the disease, which ultimately causes death. Shire Human Genetics is currently involved in a trial to get the drug into the brain. Jack was not eligible for Phase I of the trial due to hydrocephalus. We continue to pray that Jack will receive intrathecal drug soon, real soon!