source: The Children’s Hospital of Philadelphia
What is Mucopolysaccharidosis Type 1?
Mucopolysaccharidosis type 1 (MPS 1) is a rare lysosomal storage disorder characterized by an abnormal build-up of various toxic materials, called glycosaminoglycans (GAGs) in the body’s cells. MPS 1 is a spectrum of disease ranging from a mild (attenuated) form, called Scheie, to severe disease, called Hurler syndrome. Hematopoietic stem cell transplantation and/or enzyme replacement therapy is the mainstay of treatment for individuals with severe MPS 1.
Causes of Mucopolysaccharidosis Type 1
MPS 1 is a genetic condition caused by disease-causing (pathogenic) changes in the IDUA gene. The IDUA gene provides the body with the instructions it needs to produce the alpha-L-iduronidase enzyme. The role of this enzyme is to break down the GAGs in the body. If the body does not produce enough of this enzyme, GAGs build up in various parts of the body and cause symptoms of disease.
MPS 1 is inherited in an autosomal recessive manner. This means that in order to have the condition, an individual needs to have two disease-causing changes in the DNA. One change must be present in the copy of the IDUA gene that the individual inherits from their mother, and another change must be present in the copy of the IDUA gene the individual inherits from their father. In individuals with MPS 1, neither copy of the IDUA gene is able to provide the proper instructions to produce the enzyme.