MPS II Research Fund


What is Hunter Syndrome?

What is Hunter Syndrome?

Hunter Syndrome is a rare and debilitating genetic disorder. It is a form of Mucopolysaccharidosis (MPS II) and is characterized by significant bone and joint disease, as well as numerous other symptoms throughout the body.

Patients suffering from Hunter Syndrome lack an enzyme in their blood that breaks down cellular waste in the body. This waste builds up and stores in the bones, tissues, organs, and muscles, and leads to some of the symptoms described below.

Treatments for Hunter Syndrome are available and there is much Hope on the horizon. Currently, an enzyme replacement therapy exists to help slow down the disease in the body, and a clinical trial is underway for a treatment to help battle the disease in the brain (only some patients are impacted by cognitive disease). In addition, there are promising gene therapy projects underway that are showing significant and promising results in the lab setting. It is hoped that these treatments will enter the clinical trial stage soon.




Estimated Hunter Syndrome Cases in Canada


Approved and Reimbursed Therapy in Canada


Next Generation Therapies Readying For Clinical Trial


Research Grant Dollars Awarded By The MPS II Fund Over Past 36 Months 


What Causes Hunter Syndrome?

Hunter Syndrome is an inherited genetic disorder caused by a deficiency of an enzyme called iduronate-2-sulfatase or I2S. Deficiency of this enzyme causes cellular waste to build up in the body and progressively store in the bones, tissues, organs, and muscles. Hunter Syndrome is estimated to occur in 1 in 130,000 live births, with 40 estimated cases in Canada and 2000 worldwide.


Genetic Condition Caused By Enzyme Deficiency

Missing or deficient enzyme (iduronate-2-sulfatase – I2S) causes cellular waste from the cells to store in the bones, tissues, organs, and muscles.  This disease is characterized as a lysosomal storage disorder.

Lysosomal Storage Leads To Progressive Symptoms

Virtually all bones, muscles, organs, and tissues in the body are affected by I2S deficiency, leading to progressive, multi-systemic and debilitating symptoms.

Treatment IS Available

The FDA, the European Commission, and Health Canada have all approved a treatment for Hunter  Syndrome.  Developed by Shire Pharmaceuticals, this enzyme replacement therapy (ERT) delivers a synthetic version of the I2S enzyme into the bloodstream and helps to dramatically slow down the disease.


Symptoms of Hunter Syndrome

There are many symptoms and associated consequences for patients suffering from Hunter Syndrome. Until recently, management of symptoms was the only course of care for patients. In 2006, the first ever treatment for Hunter Syndrome was approved by the FDA, the European Commission, and Health Canada. More information on this treatment and emerging new treatments can be found in our TREATMENT section.

Heart and Airway Disease

People suffering from Hunter Syndrome can develop respiratory failure, severe sleep apnea, and upper airway collapse.  Affected individuals may also develop numerous and recurrent respiratory infections and a thickening of the heart valves.

People with Hunter Syndrome may have a wide range of skeletal symptoms.  These can include shortened stature, bone deformities, carpel tunnel syndrome, and multiplex dysplasia.

Hearing Loss

Usually common in the second decade of life, hearing loss can be progressive and severe.

Eye and Vision Issues

While common in many other forms of MPS, it is rare for people with Hunter Syndrome to develop corneal clouding and a debilitating decrease in vision. Night vision can also become an issue for MPS II patients.

Brain and Cognitive Impairment

People with Hunter Syndrome may experience cognitive decline, though it will be difficult to diagnose this impairment until age 4-6.  Patients may also suffer from hydrocephalus.

Specialist Care

Patients battling Hunter Syndrome often visit numerous specialists to help manage their disease.  These can include, but aren’t limited to, MPS Genetics Specialists, Neurologists, Ophthalmologists, Orthopaedic Specialists, Cardiologists, ENTs, Pulmonologists,  and Rheumatologists.  

Surgical Interventions

In almost all cases of Hunter Syndrome, patients need multiple surgical procedures.  These may include skeletal corrections, heart valve replacements, and other procedures.

Decreased Endurance

Studies have shown that endurance of affected individuals is impacted greatly due to the progression of the disease.  Endurance has an impact on all facets of life.  Recent clinical trials have shown a significant increase in endurance for all patients receiving enzyme replacement therapy.


" The condition was considered terminal and no treatment existed…Then hope came in the form of Enzyme Replacement Therapy. "
Deb Purcell – Mother of a child with Hunter Syndrome and founder of the MPS II Fund in Canada



Emerging and Exciting New Treatments

While ERT with Elaprase has dramatically altered the outlook of Hunter Syndrome over the past decade, emerging new treatments will be the future gold-standard of care for patients. Curative solutions are being investigated in the lab setting which include gene therapy projects and gene editing ideas. Clinical trials in humans are set to begin soon and it is hoped these new treatments will finally provide our patients and families with the cure we have all been looking for.

Gene Therapy for MPS II - A Curative Solution?

There are numerous Gene Therapy projects being studied in research labs around the world, with a few promising ones almost ready for clinical trials in humans. These gene therapy approaches to dealing with Hunter Syndrome have been shown to stop and correct the vast majority of symptoms, including cognitive decline, in the lab setting. Contact us directly so we can share any information we have.

Other Innovative Projects

Shire Pharmaceuticals currently has a clinical trial underway that delivers enzyme directly to the brain of patients suffering or at risk of suffering from cognitive decline as a result of the disease.  Phase I/II results have looked impressive and a Phase III trial is currently underway.


Support for Accessing Treatment in Canada

If you would like assistance obtaining ELAPRASE treatment in Canada, please don’t hesitate to contact us and we will do whatever we can to assist.

We can join you for a meeting with your Member of the Provincial Parliament (MPP) or  Member of the Legislature (MLA) and work closely with them to ensure reimbursement for treatment is forthcoming.  We can also help you connect with other families undertaking the same processes, connect with the drug company that makes ELAPRASE (Shire Pharmaceuticals) on your behalf, and come meet with you in your home province to help support you in any way necessary.

Whatever we can do to help, we’ll be here.

If you would rather connect with us via social media, please find us on the links below:

Hunter Syndrome in Canada




News from the MPS II Fund

Trey has graduated!

Hello everyone! It has been a long time since my last update. This means good news. Trey continues to do well. There are little blips that come up in terms of concerns and worries, but nothing major. However, I know it is time to update when people start asking how Trey is doing and asking if we are still researching

Read More

A small update

Dear MPS II Fund supporters, It has been 6-months since I posted an update on Trey’s website and longer since I sent out an email. I apologize for my silence. So much has happened in the last year. Our family spent a year in Los Angeles so I could pursue my dream of training as a Narrative Therapist. We are

Read More

MPS II Research Grant Provided to Dr. Laura Rigon!

There has been a LOT going on in our MPS II world as of late, funding an MPS II research grant being one of the lot! Funding research provides hope, excitement, and the possibility that perhaps our sons with MPS II (including the yet to be diagnosed sons), might have a different path. We need hope like we need air.

Read More


Talk to a Hunter Syndrome Parent

If you would like to talk directly with other parents of Hunter Syndrome patients in Canada, please fill out your information and one or more will contact you as soon as possible.  When things get stressful and tough, sometimes it helps to speak with someone in similar circumstances, fighting the same battle that you are.

At the same time, sometimes it’s just nice to connect! Whatever the reason, if you’d like to talk with a “Hunter Mom or Dad”, we’ll connect you right away.

If you would rather connect with us via social media, please find us on the links below:


We want to hear from you! Send us your story so we can share it with the world. Every person and family battling Hunter Syndrome has a unique story to tell - one of bravery, resilience, and perseverance. We'll share all stories online here and on our social media feeds!