What is MPS1


The terms Hurler, Hurler-Scheie and Scheie have historically been used. The disease was divided into 3 categories: Hurler indicates the most severe form of the disease, Scheie the less severe form, while Hurler-Scheie patients were between these two extremes. Hurler's disease derives its name from Gertrud Hurler, the pediatrician who in 1919 described a boy and a girl with that condition. In 1962 Dr. Scheie, an ophthalmologist described some of his patients whose illness was less progressed.


The main difference between Hurler and Scheie patients is that in the first there is an impairment of the nervous system, whereas this is not the case with Scheie patients.

Because it is not always easy to classify all patients into three categories, the term "MPS I" is used more often, which stands for mucopolysaccharidosis type I. To distinguish between patients with or without the nervous system. Impaired, physicians talk about the neuropathic form and the non-neuropathic form.




MPS I is a hereditary lysosomal storage disorder and is caused by a deficiency of the enzyme alpha-L-iduronidase. That enzyme is needed to break down certain substances in the body, namely glycosaminoglycans (also called GAGs). Glycosaminoglycans are complex substances that the body produces and that are found in all types of connective tissue. Connective tissue provides structural support to organs and tissues and forms the cartilage of growing bones, joints and heart valves. If this enzyme is not present in sufficient quantities, then GAGs accumulate in virtually all organs of the body, leading to this disease.



The incidence of MPS I is estimated at about 1 in 100,000 births.

Although patients with this disease have the same enzyme deficiency, they can show a whole range of different symptoms and the severity of the disease can vary from light to heavy (for more information see How does MPS I affect the body?)