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Scientific literature and patient education texts

Hunter Syndrome – A Rare Genetic Disease

key information

source: Takeda

year: 2020


Whether your son or someone you know has recently been diagnosed with Hunter syndrome, or is living with the condition, this resource has been developed to provide you with information and support with stories from families living with Hunter syndrome.

What Is Hunter Syndrome?

Hunter syndrome, also known as mucopolysaccharidosis type II (MPS II), is a rare genetic disease almost exclusively affecting boys. It is estimated that the condition is present in 1 in every 162,000 new-born babies. Hunter syndrome can affect any part of the body and has a number of signs and symptoms. In the majority of children these begin to show between the ages of 2 and 4 years.

What Causes Hunter Syndrome?

Hunter syndrome is a genetic disease caused by the deficiency or absence of an enzyme called iduronate-2-sulfatase (I2S). In Hunter syndrome, the gene that codes for I2S contains a mutation (a change), which means that the enzyme is produced with errors that stop it working properly, or the enzyme is not produced at all. I2S is essential for breaking down particular molecules, known as glycosaminoglycans (GAGs). If I2S is deficient or absent, as in Hunter syndrome, GAGs build up, which prevents cells from functioning properly.


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