MPS II (Hunter Syndrome)
MPS II is a mucopolysaccharide disease known as Hunter syndrome. It takes its name from Charles Hunter, the professor of medicine in Manitoba, Canada, who first described two brothers with the disease in 1917. MPS II has a wide range of symptoms that vary in severity and can be managed and treated with enzyme replacement therapies. There is no cure for MPS II.
What causes the disease?
Mucopolysaccharides are chains of sugar molecules used to build 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
The body constantly replaces used materials and breaks them down for disposal. MPS II patients are missing the enzyme iduronate sulfatase, which is essential to breaking down the mucopolysaccharides dermatan and heparan sulphate. These materials remain stored in the body’s cells, causing progressive damage. Babies may show little sign of the disease, but as cells sustain damage, symptoms start to appear.
How common is Hunter Syndrome?
This is a rare condition affecting 1 in 100,000 to 1 in 170,000 primarily males.
How is the disease inherited?
MPS II primarily occurs in boys, and girls may be carriers of the gene for MPS II. Although rare, MPS II has been diagnosed in girls. If the mother is a carrier, there is a 50 percent chance 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 percent chance of passing the syndrome to a son.
Is there a cure for MPS II?
There is no cure, but treatments like enzyme replacement therapies can help make the disease more manageable.
Clinical trials are research studies that determine whether treatments or devices are safe for humans. These studies also look for effective medical approaches for specific conditions and help provide reliable data for patients, researchers and doctors.
Clinical trials are conducted on small groups to determine whether a drug or procedure causes negative reactions or unsatisfactory side effects.
MPS II clinical trials, observational and natural history studies
Enzyme replacement therapy (ERT)
Enzyme replacement therapy (ERT) uses an intravenous solution (IV) to replace a deficient or missing enzyme in the body. ERT does not cure the disease but slows its progress by increasing the amount of missing enzyme in the body.
Elaprase™ (idursulfase) is a long-term enzyme replacement therapy for patients with a confirmed diagnosis of MPS II and has been approved for use in the U.S., Canada and many countries in Europe. Elaprase was developed and is produced by Shire Pharmaceuticals and is given as weekly infusions.