Mucopolysaccharidosis type IIIA

Is carrier testing available for relatives of people with mucopolysaccharidosis type IIIA?

While a diagnosis of mucopolysaccharidosis type IIIA (MPS IIIA) is typically confirmed by a biochemical genetic test called an enzyme assay, carrier testing with an enzyme assay is generally unreliable due to a wide variation in enzyme concentrations. If molecular genetic testing (which looks at the DNA) has been done on the affected family member and the mutation(s) have been identified, molecular genetic testing can then also be used to identify carriers among siblings or other relatives.

If a carrier of MPS IIIA is concerned about having an affected child, his/her partner can be screened for the most common mutations known to cause the condition. If no mutation is found in the partner, that person's risk to be a carrier would decrease significantly but would not be eliminated.

People interested in obtaining more specific information about genetic testing and/or carrier screening for MPS IIIA should speak with a genetics professional.

Last updated on 05-01-20

What testing options are available for people with a family history of mucopolysaccharidosis type IIIA?

The specific testing options for people with a family history of MPS IIIA depend on several factors which may include the specific relationship to the affected person; whether the affected person's mutation(s) are known; and whether other people in the family have been tested (and their results). A genetic counselor can help people with questions determine what their genetic risks are, whether testing is appropriate, who might benefit from testing, and what the testing options in each case are.

In many cases, health insurance will cover the costs of genetic testing when it is recommended by a physician or other health care provider. However, insurance companies have different policies about which tests are covered. Some insurers have specific requirements for the reason (indication) for testing to qualify for coverage. People with questions about coverage for a specific genetic test should check with their insurance company.

Last updated on 05-01-20

Might there be a treatment or cure for mucopolysaccharidosis type IIIA in the near future?

Studies investigating potential treatments for mucopolysaccharidosis type IIIA (MPS IIIA) are ongoing. Presently, the use of enzyme injections directly into the central nervous system are being investigated, with clinical trials underway.

Research has shown that viral-delivered gene therapy in animal models can stop the buildup of storage materials in brain cells and improve learning and memory. Researchers are planning additional studies to understand how gene therapy prompts recovery of mental function in these animal models. However, it may be years before such treatment is available to humans.

Last updated on 05-01-20

Is prenatal diagnosis available for mucopolysaccharidosis type IIIA?

Prenatal diagnosis is available for couples with an increased risk to have a baby with mucopolysaccharidosis type IIIA (MPS IIIA). The most commonly used method is a direct enzyme test on material obtained by chorionic villus sampling (CVS) at 10-12 weeks gestation. Enzyme activity can also be measured in cultured cells obtained by amniocentesis, but the method involving CVS avoids the need for tissue culture and provides results earlier and more quickly.

Fetal enzyme activity can also be measured in dried fetal blood spots; however, this is typically reserved for cases of hydrops fetalis, a common feature of MPS type VII.

People interested in learning more about prenatal diagnosis for MPS IIIA should speak with a genetics professional.

Last updated on 05-01-20

Where can I view information about clinical trials for the treatment of mucopolysaccharidosis type IIIA?

The U.S. National Institutes of Health (NIH), through the National Library of Medicine, developed to provide patients, family members, and members of the public with current information on clinical research studies. To find trials involving mucopolysaccharidosis type IIIA, click on the link below. After you click on a study, review its "eligibility" criteria to determine its appropriateness. Use the study’s contact information to learn more. Check this site often for regular updates.

You can also contact the Patient Recruitment and Public Liaison (PRPL) Office at the NIH. We recommend calling 1-800-411-1222 to speak with a specialist who can help you determine if you are eligible for any clinical trials. If you are located outside the United States, and would like to be contacted via telephone, you will need to contact PRPL and provide your telephone number in full, including area code and international dialing prefix.

Patient Recruitment and Public Liaison Office
NIH Clinical Center
Bethesda, Maryland 20892-2655
Toll-free: 1-800-411-1222
Fax: 301-480-9793
Web site:

You can find information about participating in a clinical trial as well as learn about resources for travel and lodging assistance, through the Get Involved in Research section of our Web site.

Last updated on 05-01-20

How might mucopolysaccharidosis type IIIA be treated?

Unfortunately, there is currently no cure or standard treatment for people with mucopolysaccharidosis type IIIA (MPS IIIA). Affected people and their families should consult with a medical genetics team for information about the diagnosis, counseling, up-to-date treatment options, and referrals to support groups and organizations. Treatment requires ongoing care with trained pediatric specialists in various medical fields. A consultation with a developmental pediatrician is especially helpful in addressing behavioral concerns and to assist parents and caregivers in establishing a sleep routine.

Currently, drug therapy is not part of the standard of care for MPS IIIA. Medications are used to relieve symptoms (such as anticonvulsants for seizures) and improve quality of life. Sedatives and melatonin have been used to improve the quality of sleep along with establishing a bedtime routine. Specific therapies such as bone marrow transplantation and enzyme replacement therapy (ERT) are currently not options for patients with MPS IIIA. Hematopoietic stem cell transplantation has shown mixed results and an unclear neurocognitive benefit. Recombinant enzymes for the deficiencies in MPS III are available, but trials in ERT have not been favorable in improving prognosis because the enzymes are not able to enter the central nervous system. Changes to the diet do not prevent disease progression, but limiting milk, sugar, and dairy products has helped some people who have excessive mucus.

Last updated on 05-01-20

Name: Canadian Society for Mucopolysaccharide and Related Diseases Inc. (Canadian MPS Society) #218-2055 Commercial Drive Vancouver, BC V5N OC7
Phone: 604-924-5130 Toll Free: 800-667-1846 Fax : 604-924-5131 Email: Url:
Name: Metabolic Support UK 5 Hilliards Court Sandpiper Way
Chester Business Park
Chester, CH4 9QP, United Kingdom
Phone: 0845 241 2173 Toll Free: 0800 652 3181 Email: Url:
Name: National MPS Society P.O. Box 14686
Durham, NC, 27709-4686, United States
Phone: +1-919-806-0101 Toll Free: 1-877-MPS-1001 (1-877-677-1001) Fax : +1-919-806-2055 Email: Url:
Name: Society for Mucopolysaccharide (MPS) Diseases MPS House Repton Place White Lion Road Amersham Buckinghamshire
United Kingdom
Phone: (+44) 0345 389 9901 Email: Url:
Name: Hide and Seek Foundation for Lysosomal Storage Disease Research 6475 East Pacific Coast Highway Suite 466
Long Beach, CA, 90803 , United States
Toll Free: (844) 762-7672 Email: Url:
Name: Team Sanfilippo Foundation PO Box 1152
Ronkonkoma, NY, 11779, United States
Phone: 518-879-6571 Email: Url:
Name: Cure Sanfilippo Foundation PO Box 6901
Columbia, SC, 29260,
Phone: 803-413-0525 Email: Url:

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