About Sanfilippo Syndrome
Sanfilippo syndrome is the name families and clinicians use for mucopolysaccharidosis type III. It comes in four subtypes, A through D, each caused by the loss of a different enzyme in the chain that breaks down heparan sulfate: heparan sulfamidase in type A, alpha-N-acetylglucosaminidase in type B, acetyl-CoA alpha-glucosaminide N-acetyltransferase in type C, and N-acetylglucosamine-6-sulfatase in type D. Whichever enzyme is missing, the result is the same: heparan sulfate accumulates inside cells, above all in the brain, where partially broken-down fragments are toxic to nerve cells and set off inflammation and cell death.
What makes Sanfilippo different from the other MPS disorders is where it strikes. The physical signs that mark Hurler or Hunter syndrome are mild here, limited to slightly coarse features, an enlarged liver and spleen, and some skeletal changes. The brain takes the full weight of the disease. Children appear healthy at birth and through infancy, and the first signs, usually between ages 2 and 6, look like a behavioral or developmental problem: hyperactivity, a plateau in development, delayed speech. What follows is a relentless childhood dementia. Words already learned disappear, skills already mastered unwind, and behavior deteriorates into severe intellectual disability. Movement goes next, with loss of coordination, an unsteady gait and eventually the inability to walk. Sleep disturbance is common and severe, particularly in type A, and seizures develop in about 3 of every 4 children in the later stages. Type A progresses fastest and type C somewhat slower, but every form leads to profound disability.
Common Symptoms of Sanfilippo Syndrome
Recognizing the signs of Sanfilippo Syndrome early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.
- Behavioral problems and psychiatric symptoms starting in childhood
- Progressive intellectual disability and cognitive decline
- Loss of speech and language abilities
- Progressive motor deterioration and movement disorders
- Sleep disturbances and hyperactivity
- Seizures in later stages
Who Sanfilippo Syndrome Affects
Sanfilippo syndrome typically shows itself between ages 2 and 6, usually as behavioral change or a stall in development, with progressive neurological decline following. There are 4 genetic subtypes, A through D, with different rates of progression; type A is the most common and the fastest. It affects boys and girls equally and is inherited in an autosomal recessive pattern, meaning both parents carry a copy without symptoms. It is most frequent in Scandinavian and Aboriginal Australian populations.
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FDA-Approved Treatments for Sanfilippo Syndrome
There is currently 1 FDA-approved medication for Sanfilippo Syndrome. These therapies represent the current standard of care and may be used alongside or compared against investigational treatments in active clinical trials.
Source: openFDA drug labeling data. This list may not include all treatments. Always consult your doctor.
Help Paying for Sanfilippo Syndrome Treatment
Charity funds and drugmaker programs for Sanfilippo Syndrome, checked at the source. Pick your insurance to see what fits.
- From a charity · TotalAssist (formerly PAN Foundation)Mucopolysaccharidosis Type III (Sanfilippo) fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $2,500 per year. Requires health insurance (any kind).
- From a charity · National MPS SocietyFamily Assistance Program fundApply directly
Pays for: Specialized equipment and medical aids not covered by insurance (requires insurance denial and 10% family copay), up to $3,000 per year.
The foundation says: “Status not shown on page” - From a charity · National MPS SocietyMedical Travel Assistance Program fundApply directly
Pays for: Travel to out-of-town medical appointments more than 125 miles away (per year), up to $550 per year.
The foundation says: “Status not shown on page” - From a charity · National MPS SocietyJourney Assistance Program fundApply directly
Pays for: Items that ease daily life (40% of purchase price), up to $500 per year.
The foundation says: “Status not shown on page”
Side Effect Explorer
Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.
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Genetic Testing
Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.
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Trusted Sanfilippo Syndrome Resources
Reputable organizations and medical references for learning more about Sanfilippo Syndrome, including disease registries, foundation resources, and clinical guidelines.