What is Hunter Syndrome or MPS II?
Hunter syndrome, or mucopolysaccharidosis II (MPS II), is a serious genetic disorder that primarily affects boys. 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 GAGs. Mucopolysaccharides are long chains of sugar molecule used in the building of connective tissues in the body.
- “muco” refers to the thick jelly-like consistency of the molecules
- “poly” means many
- “saccharide” is a general term for a sugar molecule (think of saccharin)
The body has a continuous process of replacing used materials and breaking them down for disposal. Children with MPS II are missing an enzyme called iduronate sulfatase which is essential in cutting up the mucopolysaccharides called dermatan and heparan sulphate. The incomplete broken down mucopolysaccharides remain stored in cells in the body causing progressive damage. Babies may show little sign of the disease, but as more and more cells become damaged, symptoms start to appear.
How common is Hunter Syndrome?
This is a rare condition affecting 1 in 100,000 to 1 in 150,000 males. There is an estimate in the United States that 1 in 25,000 births will result in some form of MPS.
How is the disease inherited?
MPS II occurs in boys, and girls may be carriers of the gene for MPS II. Although rare, MPS II has been diagnosed in girls.
All families of children with MPS II should seek further information from their doctor or genetic counselor before planning to have more children. If the mother is a carrier, there is a 50% risk that any boy born will have the disease.
The sisters and maternal aunts of a person with MPS II may be carriers of the disease and would also have a 50% chance of passing the syndrome to a son. There are tests available for carriers, so it is important for all female relatives on the mother’s side to seek advice from their doctor.
What are the signs and Symptoms?
The symptoms of Hunter syndrome (MPS II) are generally not apparent at birth, but usually start to become noticeable after the first year of life.
Common early symptoms of Hunter syndrome may include:
- inguinal hernia
- ear infections
- runny nose
- colds
Is there a Cure for MPS II?
There is no cure but treatments such as enzyme replacement therapies can help make the disease more manageable. On July 24, 2006, the FDA granted marketing approval for ELAPRASE® (idursulfase), the first FDA approved enzyme replacement therapy for the treatment for MPS II, also known as Hunter syndrome. For more information on the treatment, visit http://www.elaprase.com/.
Where Can I find More Information?
National MPS Society — The National MPS Society supports families and individuals affected by MPS and related diseases. They work to advance scientific research and increase public and professional awareness of MPS.
Dancing with Dominic 
Hunter Syndrome is an incredibly rare and very severe disease. Current treatments for MPS 2, including enzyme replacement therapy and bone marrow transplant, do not directly deal with the disease but rather only remedy the symptoms of the disease. This is because current treatments are unable to penetrate the Blood-Brain Barrier (BBB), which prevents uptake of 100% of large molecule therapies. Currently, there is a treatment being investigated that may be able to penetrate the BBB, and potentially cure Hunter Syndrome. No matter what, finding a cure for this disease will require a collaborative effort of individuals and organizations across the globe. You can find more of these organizations here:
http://breakingbarriershuntertrial.com/hunter-support-groups/