MPS I education for you
What is mucopolysaccharidosis type I (MPS I)?
Mucopolysaccharidosis type I (MPS I) is a rare genetic condition that runs in families. It has a wide range of symptoms because it can affect many parts of the body and cause organ damage. People with MPS I are described as having either a severe form (Hurler syndrome) or attenuated form (Hurler-Scheie or Scheie syndrome) based on the age of onset, severity of symptoms, rate of disease progression, and whether there is any early and direct involvement of the brain.
Like all LSDs, MPS I is chronic and progressive, meaning it can get worse over time. Symptoms often go unrecognized and misdiagnosed; however, the earlier MPS I is diagnosed, the sooner it can be appropriately managed.
If you think you or a family member may have MPS I, talk to a doctor about possible next steps such as getting tested.
What causes MPS I?
MPS I is caused by changes in the IDUA gene. This gene produces an enzyme called alpha-L-iduronidase or IDUA. Alterations in the IDUA gene result in reduced IDUA production.
IDUA is responsible for breaking down sugars called glycosaminoglycans or GAGs. Reduced IDUA can result in a buildup of GAGs, which can interfere with the normal function of cells and cause progressive damage.
What are common MPS I symptoms?
MPS I affects multiple organs in the body, which results in a spectrum of symptoms and symptom severity. People may also experience different symptoms as the disease advances. MPS I typically presents with distinctive facial features, such as a large head, flat face, broad short nose, and large tongue. Common symptoms can include:
- Reduced eyesight, corneal clouding
- Hearing loss, frequent ear infections
- Cognitive impairment, developmental delay (typically not present in attenuated form)
- Difficulty breathing, frequent respiratory infections
- Protruding abdomen due to enlarged spleen and liver
- Significant orthopedic issues: curved spine, spinal cord compression, carpal tunnel syndrome, knocked knees, delayed growth
- Pain in chest, abdomen, hands, and fingers
- Joint pain, joint stiffness, reduced movement
- Heart issues, thickening and dysfunction of heart valves
*These are not all possible symptoms, nor do all patients have all the listed symptoms.
Who does MPS I affect?
MPS I can affect males and females of all ages. The estimated prevalence of severe MPS I is 1 in 100,000. The estimated prevalence of attenuated MPS I is 1 in 500,000.
How is MPS I inherited?
MPS I is an autosomal recessive condition, meaning it takes changes in both copies of their IDUA gene to cause MPS I. Children inherit two copies of each gene from their biological parents (one copy from the mother, one copy from the father).
A person who has only one copy of the changed IDUA gene is called a carrier. They do not have MPS I or experience symptoms.
When both parents are carriers, with each birth there is a 25% chance that their child will have MPS I; 25% chance that their child will not have MPS I or carry the altered IDUA gene; and 50% chance that their child will be a carrier only without having the condition.
Sign up for personalized support
At CareConnect, we offer personalized support and resources to help you and your family navigate life with MPS I. Your Patient Education Liaison (PEL) can assist you with disease and Sanofi treatment education, and information about inheritance patterns, genetic assessment and testing options. Your Case Manager can talk to you about health insurance, financial assistance, and care coordination.
Keep in mind: Your healthcare team is always the best source of information and point of contact if you have any questions or concerns about your health.
If you’re not enrolled and interested in speaking with a CareConnect team member, a Case Manager is available to speak with you Monday through Friday, 8AM-6PM EST.
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Call 1-800-745-4447 or email info@CareConnectPSS.com.
Alternatively, you can click the button below to request more information by email.
Explore more resources
Learn more about MPS I at mps1disease.com
MAT-US-2409361-v1.0-11/2024. Last Updated: November 2024