Hunter syndrome is an inherited disorder where glycosaminoglycans (GAGs) build up in cells of the body due to a deficiency of the enzyme iduronate-2-sulfatase.
There is no cure for the syndrome and treatment is aimed at managing the condition so as to ease symptoms and provide some relief for the sufferer. This is referred to as palliative treatment and the objective is to minimize negative effects on bodily functions as the condition worsens.
Some emerging treatments have also been shown to help slow disease progression and decrease the severity of the syndrome.
Some of these treatments include:
- Bone marrow transplantation – In milder cases of Hunter syndrome, bone marrow transplantation may be performed to provide a new source of the deficient iduronate-2-sulfatase. Bone marrow is taken from the hip of a healthy donor who matches the patient’s blood and tissue type. The bone marrow is transplanted through intravenous injection. This transplantation can help improve respiratory problems and the function of major organs such as the heart, liver and spleen. Mobility may also be improved and mental regression prevented. However, the treatment does not improve problems associated with vision or the bones.
- Enzyme therapy – This therapy involves the use of synthetic enzymes to restore levels of the deficient iduronate-2-sulfatase enzyme. The therapy is called idursulfase or Elaprase and was first developed by the company Shire Plc. The therapy is administered intravenously once a week and may delay or prevent some symptoms of this syndrome developing if administered early enough in the disease course. However, it is unclear whether the benefits of therapy are significant enough to improve patient’s quality of life and no improvements in mental decline have yet been observed as a result of the treatment. Furthermore, the drug is one of the most expensive to have ever been produced, costing USD 375,000 per patient, per year.
- Gene therapy – Researchers are currently investigating the possibility of replacing the chromosome responsible for iduronate-2-sulfatase, which technically could cure Hunter syndrome.
Reviewed by Sally Robertson, BSc