No, it’s nothing to do with arrows, or wellies.
Mucopolysaccharidosis is actually a range of genetic disorders, all of which are due to a lack of an enzyme. Enzymes do different jobs around the body, and these particular ones normally break down long chain sugar molecules (GAGs) once they have been finished with. In an affected individual without the enzyme, these sugar chains build up throughout the body – in organs and joints – causing a wide range of problems.
Hunter Syndrome (or Hunter Disease) – MPS Type II – has in the past been described as mild or severe, but is now recognised as comprising a wide spectrum of severity. It is the only one of the MPS disorders that is passed down on the X chromosone, so from the mother alone.
In recent years a new treatment, enzyme replacement therapy (ERT), has been developed. This involves an infusion over 3-4 hours to replace the missing enzyme, which works to break down the circulating sugar molecules, and those which have been stored around the body. This can mitigate many of the physical problems brought by Hunter Disease, but is unable to cross the blood-brain barrier and reduce areas affected in the central nervous system.
When there is CNS involvement, intellectual development slows and life expectancy is severely reduced. Research into possible treatments is continuing, including a clinical trial currently running in a number of countries.
For more information on any of the MPS disorders, please visit the The Society for Mucopolysaccharide Diseases (the MPS Society) where there is loads of helpful information and advice.