What is MPS-I?
MPS-I, (Mucopolysaccharidosis Type I) is a disease that is relentlessly progressive and potentially fatal. MPS-I has also been called Hurler, Hurler-Scheie and Scheie Syndrome. There is no cure for MPS diseases, but there are ways of managing and treating the problems they cause.
MPS-I is a rare genetic metabolic disorder caused by the absence of lysosomal enzymes needed to break down molecules called glycosaminoglycans (long chains of sugar carbohydrates in each of our cells) that help build bone, cartilage, tendons, corneas, skin and connective tissue. Glycosaminoglycans are also found in the fluid that lubricates our joints.
People with a MPS-I disease do not produce enough of the enzyme required to break down these sugar chains into simpler molecules. Over time, these sugars collect in the cells, blood and connective tissues. The result is permanent, progressive cellular damage which affects appearance, physical abilities, organ and system functioning, and, in most cases, mental development.
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). Vocal cords can also enlarge, resulting in a deep, hoarse voice. The airway may become narrow in some people with MPS-I, causing frequent upper respiratory infections and short pauses in breathing during sleep (sleep apnea).
People with MPS-I often develop clouding of the clear covering of the eye (cornea), which can cause significant vision loss. Affected individuals may also have hearing loss and recurrent ear infections.
Individuals with MPS-I usually have short stature and joint deformities (contractures) that affect mobility. Most people with the disorder also have dysostosis multiplex, which refers to multiple skeletal abnormalities. Carpal tunnel syndrome develops in many children with this disorder and is characterized by numbness, tingling, and weakness in the hand and fingers. Narrowing of the spinal canal (spinal stenosis) in the neck can compress and damage the spinal cord.
People with MPS-I can experience a decline in intellectual function and a more rapid disease progression. Developmental delay is usually present by age 1, and severely affected individuals eventually lose basic functional skills (developmentally regress). In this form of the disorder, death typically occurs by age 10. Individuals with attenuated MPS-I typically live into adulthood and may or may not have a shortened lifespan. Some people with the attenuated type have learning disabilities. Heart disease and airway obstruction are major causes of death in people with both types of MPS-I.
MPS-I occurs in between 1:100,000 and 1:500,000 newborns.
More information can be found at the National MPS Society – www.mpssociety.org
Much of this information was found at – http://ghr.nlm.nih.gov/condition/mucopolysaccharidosis-type-i