Hunter Syndrome (MPS II)
About the Disease | Signs / Symptoms | Diagnosis | Treatment | Sample Requirements l Results and Turnaround Time l Shipping l CPT Codes
About the Disease
Hunter Syndrome is also known as mucopolysaccharidosis type II (MPS II) or iduronate 2-sulfatase (IDS) deficiency.
How common is Hunter syndrome?
It has been estimated that about 1 in every 100,000 newborn males has Hunter syndrome.
Are there different types of Hunter syndrome?
MPS II represents a wide spectrum of disease severity. Some individuals with Hunter syndrome are mildly affected with normal intelligence, mild clinical symptoms and long lifespans. Other individuals with MPS II are much more severely affected and have progressive developmental delay, severe physical involvement and greatly reduced life expectancies. Still other patients will have an intermediate form of the disorder with normal to near normal intelligence but significant physical problems.
What causes someone to have Hunter syndrome?
Hunter syndrome is a disorder caused by a deficiency of the enzyme iduronate sulfatase (IDS). IDS is responsible for breaking down long chain sugar molecules called glycosaminoglycans (GAGs). GAGs are normally produced by the body and are used in the formation of bones, cartilage, skin, tendons and many other tissues. GAGs are normally broken down and recycled by several enzymes including IDS. In Hunter syndrome, an affected individual has absent or much decreased amounts of IDS, causing GAGs to build up in the up in various tissues of the body. The progressive build-up of GAGs causes the symptoms seen in Hunter syndrome.
How is Hunter syndrome inherited?
The gene for Hunter syndrome is located on the X chromosome. Males have one X chromosome while females have two. Thus, a mutation (change) in the gene for Hunter syndrome would cause the disease in a male child, but not typically in a female. Mothers who are silent carriers may pass the gene for Hunter syndrome to their children. Women who have a mutation in one of their genes for Hunter syndrome have a 25% chance of having a boy with Hunter syndrome and a 25% chance of having a girl who carries Hunter syndrome in each pregnancy.
Back to Top
What are the signs and symptoms of Hunter Syndrome?
Hunter syndrome is a progressive disorder. Typically, newborns with Hunter syndrome show no signs of the condition. A child with more severe Hunter syndrome may have decelerating growth during the first two years of life, developmental delay, frequent ear and sinus infections and rhinorrhea, breathing difficulties, and a gradual coarsening of his facial features. The liver and spleen are typically enlarged, abdominal and/or inguinal hernias are common, and behavioral hyperactivity or irritability is often reported. Gradually, bone and joint problems develop, respiratory complications increase, and the child may begin to lose developmental skills. Unfortunately, many individuals with more severe Hunter syndrome die before reaching adulthood.
A child with milder Hunter syndrome typically does not have the developmental or behavioral concerns seen in the more severely affected children. Mildly affected individuals may have many of the same physical characteristics seen in more severely affected individuals, although these characteristics tend to develop at a slower rate. Problems with the bones and joints, respiratory difficulties, hearing loss, and later-onset heart disease are common medical complications of mild Hunter syndrome. Individuals with milder symptoms may have a near-normal life expectancy.
Back to Top
How is Hunter syndrome diagnosed?
A doctor usually suspects Hunter syndrome (or related disorder) in a child with typical facial features and perhaps developmental delay. Hunter syndrome can be confirmed by three different methods: 1) documenting increased urinary excretion of dermatan sulfate and heparan sulfate; 2) measuring iduronate 2-sulfatase activity in skin fibroblasts, plasma, or peripheral leukocytes to determine deficiency or; 3) by documenting the presence of a mutation in the IDS gene. Biochemical and genetic testing results usually do not predict the severity of the disorder. Genetic confirmation of the mutation in the proband allows for accurate carrier testing in at-risk females and prenatal diagnosis or preimplantation genetic diagnosis in future pregnancies.
Back to Top
How is Hunter syndrome treated?
No cure yet exists for Hunter syndrome. Bone marrow and stem cell transplantation have yielded mixed results and are not expected to affect the neurologic symptoms of the disorder. Current treatment focuses on managing the developmental delays, behavioral problems, and physical symptoms of Hunter syndrome. Enzyme replacement therapy has shown great promise in ameliorating many of the debilitating physical symptoms of Hunter syndrome and is expected to be approved for clinical use by the FDA in Fall, 2006.
Back to Top
Sample Requirements
Blood samples should be collected in EDTA (lavender topped) tubes. A minimum of 5cc on adult or 3cc on child is required for analysis. Blood collected on Friday may be stored in refrigerator until Monday for overnight shipment. For other tissue requirements please call 1-800-344-2462, extension 4474.
Back to Top
Results and Turnaround Time
Reports are routinely available within 3 weeks of sample receipt. Abnormal results will be called to the referring physician. Reports will be faxed to the referring physician.
Back to Top
Blood Sample Packaging and Shipping Instructions
Blood samples must be sent to the laboratory by overnight courier (Federal Express). DO NOT SHIP SAMPLES ON A FRIDAY.
All samples must be clearly labeled with the patient's name and birth date and should be initialed by the phlebotomist to attest to the patient's identity on the label.
- Please enclose the appropriate test requisition with sample. All information must be completed before sample can be processed.
- All samples must be clearly labeled with the patient's name and birth date and initialed by the phlebotomist.
- All samples should be wrapped, cushioned against breakage and sealed in a plastic bag before placement in the shipping container.
- All samples should be sent at room temperature.
- Do not allow to freeze.
- Samples should be sent by overnight carrier to arrive Monday through Friday.
- Keep a copy of requisition form for your records.
Ship Samples To
Molecular Genetics Laboratory
Cincinnati Children's Hospital Medical Center
3333 Burnet Ave., NRB 1042
Cincinnati, OH 45229
513-636-4474
Back to Top
CPT Codes
Please call 866-450-4198 for current pricing.
| Test |
CPT Code |
| Hunter Full Gene Sequencing |
83890, 83898 (x10), 83894 (x10), 83891 (x10), 83904 (x20), 83909 (x20), 83912 |
| Hunter Family Mutation Studies |
83890, 83898, 83894, 83891, 83904, 83912 |
Back to Top
