Hurler syndromeAlpha-L-iduronate deficiency; Mucopolysaccharidosis type I; MPS I H
Hurler syndrome is a rare disease of metabolism in which a person cannot break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides).
Metabolism refers to all the physical and chemical processes in the body that convert or use energy, such as:BreathingCirculating bloodControlling bo...
Hurler syndrome belongs to a group of diseases called mucopolysaccharidosis, or MPS.
- MPS II (Hunter syndrome)
- MPS IV (Morquio syndrome)
- MPS III (Sanfilippo syndrome)
- MPS I S (Scheie syndrome)
People with Hurler syndrome do not make an enzyme called lysosomal alpha-L-iduronidase. This enzyme helps break down long chains of sugar molecules called glycosaminoglycans . These molecules are found throughout the body, often in mucus and in fluid around the joints.
Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For example, they can help break down the foods we eat ...
Without the enzyme, glycosaminoglycans build up and damage organs, including the heart. Symptoms can range from mild to severe.
Hurler syndrome is inherited, which means that your parents must pass the disease on to you. If both parents carry a nonworking copy of the gene related to this condition, each of their children has a 25% (1 in 4) chance of developing the disease.
Hurler syndrome is a type of mucopolysaccharidosis called MPS I. It is the most severe type. It is categorized as MPS I H.
The other subtypes of MPS I are:
- MPS I H-S (Hurler-Scheie syndrome)
- MPS I S (Scheie syndrome)
Symptoms of Hurler syndrome most often appear between ages 3 to 8. Infants with severe Hurler syndrome appear normal at birth. Facial symptoms may become more noticeable during the first 2 years of life.
- Abnormal bones in the spine
- Claw hand
- Cloudy corneas
- Halted growth
- Heart valve problems
- Joint disease, including stiffness
- Intellectual disability that gets worse over time
- Thick, coarse facial features with low nasal bridge
Exams and Tests
These tests are done to check for Hurler syndrome:
- Genetic testing for changes to the alpha-L-iduronidase (IDUA) gene
- Urine tests for extra mucopolysaccharides
- X-ray of the spine
Enzyme replacement therapy for Hurler syndrome adds a working form of the missing enzyme to the body. The medicine, called laronidase (Aldurazyme), is given through a vein (IV, intravenously). Talk to your health care provider for more information.
Bone marrow transplant has been used in several people with this condition. The treatment has had mixed results.
Bone marrow transplant
A bone marrow transplant is a procedure to replace damaged or destroyed bone marrow with healthy bone marrow stem cells. Bone marrow is the soft, fat...
Other treatments depend on the organs that are affected.
For more information and support, contact one of the following organizations:
- The National MPS Society -- www.mpssociety.org
- Canadian Society for MPS and Related Diseases -- www.mpssociety.ca
- Society for MPS Diseases -- www.mpssociety.co.uk
Hurler syndrome is a disease with a poor outlook. Children with this disease develop nervous system problems, and can die young.
When to Contact a Medical Professional
Call your provider if:
- You have a family history of Hurler syndrome and are considering having children
- Your child begins to show symptoms of Hurler syndrome
Experts recommend genetic counseling and testing for couples with a family history of Hurler syndrome who are considering having children. Prenatal testing is available.
National Institute of Neurological Disorders and Stroke. Mucolipidoses Fact Sheet . Office of Communications and Public Liaison. Bethesda, MD; Publication No. 03-5115. February 13, 2007.
Pyeritz RE. Inherited diseases of connective tissue. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 260.
Spranger J. Mucopolysaccharidoses. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics . 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 82.
Staba SL, Escolar ML, Poe M, et al. Cord-blood transplants from unrelated donors in patients with Hurler's syndrome. N Engl J Med . 2004 May 6;350(19):1960-9. PMID: 15128896 www.ncbi.nlm.nih.gov/pubmed/15128896 .
Wraith JE. Mucopolysaccharidoses and oligosaccharidoses. In: Saudubray JM, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment . 5th ed. New York, NY: Springer; 2012:chap 40.
Low nasal bridge - illustration
A low or absent nasal bridge can occur in association with infectious diseases or genetic diseases.
Low nasal bridge
Review Date: 4/20/2015
Reviewed By: Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.