Mucopolysaccharidosis type I, often shortened to MPS I, is an inherited lysosomal storage disorder that affects many parts of the body. It was once split into Hurler, Hurler-Scheie and Scheie syndromes, and is now described as a severe and an attenuated type because the three overlap so much. Signs include a large head, coarse facial features, an enlarged liver and spleen, heart valve abnormalities, clouding of the cornea, hearing loss, joint contractures, short stature and a narrowed airway. Severe MPS I also brings intellectual decline and a shortened life, sometimes into late childhood, while the attenuated type often reaches adulthood. Mutations in the IDUA gene remove the enzyme that breaks down glycosaminoglycans, which build up inside lysosomes. Inheritance is autosomal recessive.
Facts
Classification
ICD-10 ChapterIV: Endocrine, Nutritional and Metabolic Diseases 2 Communicable or Non-communicable Transmission Route Causative Agent
Causative Agent (category) Connections
Treated By
Source National Organization for Rare Disorders: Mucopolysaccharidosis Type I
Source National Organization for Rare Disorders: Mucopolysaccharidosis Type I
Sources
1. Mucopolysaccharidosis type I (MedlinePlus Genetics)
Description, eyes
People with MPS I often develop clouding of the clear covering of the eye ( cornea ), which can cause significant vision loss.
Description, ears
Affected individuals may also have hearing loss and recurrent ear infections.
Description, heart valves
Individuals with MPS I may have a large head (macrocephaly), a buildup of fluid in the brain (hydrocephalus), heart valve abnormalities, distinctive-looking facial features that are described as "coarse," an enlarged liver and spleen (hepatosplenomegaly), and a large tongue (macroglossia).
Description, skeleton
Most people with the severe form of the disorder also have dysostosis multiplex, which refers to multiple skeletal abnormalities seen on x-ray.
Causes
Mutations in the IDUA gene cause MPS I.
Inheritance
This condition is inherited in an autosomal recessive pattern , which means both copies of the gene in each cell have mutations.
View the Source2. World Health Organization: ICD-10 Version:2019 - E70-E90 Metabolic disorders
World Health OrganizationICD-10 2019 category E76.0, Chapter IVQuote, ICD-10 2019 category E76.0, Chapter IV
E76.0 Mucopolysaccharidosis, type I
National Organization for Rare Disorders: Mucopolysaccharidosis Type I
National Organization for Rare DisordersTreated By: Enzyme Replacement Therapy, Treatment, replacing the deficient enzyme
One way is to infuse them with purified enzyme also known as enzyme replacement therapy (ERT).
Treated By: Hematopoietic Stem Cell Transplantation, Treatment, replacing the deficient enzyme
Another method to replace the enzyme in patients is to perform hematopoietic stem cell (HSCT) or bone marrow transplantation.
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