Sanfilippo (san-fuh-LEE-po) syndrome is a rare genetic
metabolism disorder. A change in a single gene makes a child's body unable to break
down certain carbohydrates (sugars). This leads to serious problems in the brain
and nervous system.
There is no cure yet for Sanfilippo syndrome. But doctors and researchers are working
hard to find better treatments for it.
What Causes Sanfilippo Syndrome?
The body makes long chains of sugar molecules called glycosaminoglycans (GAGs),
also called mucopolysaccharides. They:
help build cartilage, connective tissue, nerve tissue, and skin
help blood clot
are used in the communication between cells
The body continually builds GAGs and, when their job is done, breaks them down
One type of sugar molecule is called heparan sulfate. A child born with Sanfilippo
has a defect in one of the genes that make enzymes needed to break down
heparan sulfate. Without the gene, the used heparan sulfate builds up in the cells
and keeps them from working as they should. This can damage organs, affecting growth,
mental development, and behavior.
Four enzymes are involved in breaking down heparan sulfate, so there are four types
of Sanfilippo syndrome (A, B, C, and D), depending on which enzyme is affected. Type
A is the most common and most severe form.
A family history increases the risk for Sanfilippo syndrome, which affects about
1 in 70,000 births. The condition is also called mucopolysaccharidosis type III (MPS
What Are the Signs & Symptoms of Sanfilippo Syndrome?
Kids who have the condition are born with it. But most won't have symptoms until
the preschool years, when they're between 2 and 6 years old. Then, they start to show
developmental delays and behavioral issues. Trouble with sleep is common.