Hunter Syndrome was first discovered by DR Hunter in 1917 hence the name given to this condition. It is also known as Mucopolysaccharidosis Type II or MPS II for short. It is a rare inherited disease where sufferers experience a build-up of mucopolysaccharides, which are complex sugars, in their cells.
This is caused by a deficiency in the enzyme iduronate 2-sulfatase, which would normally break down mucopolysaccharides and prevent them from being continuously stored.
Females are the carriers of the affected gene that is passed on to their children; therefore, Hunter Syndrome primarily affects males. It is a complex condition that interferes with many biological processes in the body, and because of this, there is no current cure for this syndrome.
The build-up of sugars in the cells caused by Hunter Syndrome causes a broad spectrum of symptoms in sufferers.
Short stature due to developmental problems is a very common symptom in those with Hunter Syndrome. These individuals can also express a distinctive physical appearance that includes a larger-than-normal head, a short neck, and a wide chest.
Hepatosplenomegaly, which is the enlargement of both the liver and spleen, may also be present in sufferers along with abnormalities in the skeleton which can eventually lead to a number of joint disorders.
Other symptoms that can be experienced include frequent ear infections, hearing loss, umbilical hernias, and a general delay in the development of the body.
Genes are the cause of Hunter Syndrome and, more especially, the IDS gene, whose role is to produce the iduronate 2-sulfatase enzyme, which breaks down mucopolysaccharides.
Mutations or defects in the IDS gene lead to a deficiency in this enzyme, and the result is a build-up of complex sugars in the cells, which affect the normal functioning and development of the human body.
The obvious risk factor associated with Hunter Syndrome is if the mother expresses the gene mutation, which would place any male offspring at high risk of developing the syndrome in childhood and beyond.
The longer the condition remains undiagnosed, the greater the risk becomes of further complications occurring, such as behavioural problems, seizures, breathing difficulties, the increased risk of heart disease, and a decline in brain function.
There are several tests used by medical professionals that can confirm the diagnosis of Hunter Syndrome. These include a urine test that can identify the presence of unusually large amounts of sugar molecules.
Blood tests for enzyme levels can identify the absence or a deficiency in the essential enzymes needed to break down mucopolysaccharides, and genetic testing can find mutations.
All of these, along with the physical appearance of an individual, can help doctors make an accurate diagnosis of the presence of Hunter Syndrome in a child or young adult.
Once a diagnosis has been made, a management program can be put into action to control the symptoms and slow the progression of the disease. The main therapy is enzyme replacement therapy, physiotherapy, and surgery in extreme cases. The aim of these therapies is to improve the quality of life and extend the shorter-than-average life expectancy of those afflicted by this syndrome.