Enzyme Replacement Therapy For Hunter Syndrome

Hunter syndrome is a genetic disorder, which is extremely rare. It is caused due to an enzyme that is either completely missing or not functioning properly. This enzyme is called iduronate 2-sulfatase. If there is not enough of this enzyme present in the body, or if the enzyme is present but it does not function properly, it leads to hunter syndrome. The function of this enzyme is breaking down certain molecules that are complex in structure. If this enzyme is not in enough quantities or is absent, then these complex molecules start collecting in harmful proportions. ⁽¹⁾

When these molecules start collecting in harmful proportions, it leads to a progressive damage which affects the appearance, organ functioning, physical and mental development and abilities. Hunter syndrome is more common in boys than in girls. It is one of the different types of inherited metabolic disorders, known as mucopolysaccharidoses or MPSs. Hunter syndrome is also called by the name MPS II. ⁽²⁾

• Enzyme replacement therapy, along with some other emerging treatment methods, has shown tremendous results in hunter syndrome, by way of slowing down the progression of the disease and managing the symptoms, thereby decreasing the severity of the disease. However, the long-term effects of this therapy are yet unknown. ⁽¹⁾
• Enzyme replacement therapy is approved by the food and drug administration. This treatment method uses man-made or engineered enzymes, which replaces the missing or defective enzyme in hunter syndrome. This may ease the disease symptoms and decrease the severity of the disease. This treatment is administered through an intravenous (IV) line every once a week. ⁽³⁾
• If this treatment is started in the early phase of the disease, it may delay many symptoms of hunter syndrome and may even prevent some symptoms.
• However, whether the improvements or changes seen due to this treatment are good enough to improve the quality of life is yet not clear
• Also, there is not a significant improvement in the area of mental abilities like intelligence and thinking, with the use of this therapy
• There may also be an allergic reaction with enzyme replacement therapy in some cases, which can be quite serious
• Some may experience other symptoms like fever, skin reactions and headache
• However, these side effects may reduce or disappear with an adjustment in dose or over time in many cases

Other therapies that are emerging as treatment methods for hunter syndrome are-

• Stem cell transplant and gene therapy

• In this procedure, healthy stem cells are introduced into your body and it is expected that these new, healthy cells will make the defective or the missing enzyme
• However, so far there have been mixed results in the researches and more studies are required to establish this theory

• According to this theory, if the chromosome that is responsible for causing hunter syndrome is replaced, it may cure hunter syndrome
• However, more studies and researches are needed to confirm this before such kind of therapy can be claimed as available for the treatment of hunter syndrome

The focus of the treatment in hunter syndrome is to manage the symptoms and treat the complications arising because of the disorder. Hunter syndrome cannot be cured, and treatment aims at management of the condition. This can be different for different children.

Many complications arise when a child is suffering from hunter syndrome. The complications are related to all the major systems like respiratory system, circulatory system, nervous system and skeletal system etc. Addressing the symptoms and complications is necessary to obtain relief from the condition. Though complete cure cannot be possible, various treatment methods can help in alleviating the symptoms and improving the quality of life.

Enzyme replacement therapy can show some benefits when administered in hunter syndrome. However, more studies and researches are needed to see if this therapy can significantly improve the quality of life.

References-

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249184/
2. https://mpssociety.org/learn/diseases/mps-ii/
3. https://www.cochrane.org/CD008185/CF_enzyme-replacement-therapy-idursulfase-mucopolysaccharidosis-type-ii-hunter-syndrome

Also Read:

• Hunter Syndrome: Causes, Symptoms, Diagnosis, Treatment
• Is Hunter Syndrome Fatal & What Are Its Complications?
• Lifestyle Changes For Hunter Syndrome
• What Is The Life Expectancy Of A Person With Hunter Syndrome?
• Who Is At Risk For Hunter Syndrome?