Mucopolysaccharidosis (MPS) III, also known as Sanfilippo Syndrome, is a progressive lysomal storage disorder whose primary features and disability are due to central nervous system effects.
There are four types of MPS III (A, B, C, and D), each caused by a unique autosomal recessive genetic defect and enzyme deficiency. All types results in excessive build up of the glycosaminoglycan (GAG) heparan sulfate. Each subtype has similar signs and symptoms, which progress at varying speeds. However, features of classic MPS IIIA typically appear earlier in life and often progress more rapidly. Most children with subtype A, the most common of the four, do not live past their mid-teens.
|Sanfilippo Type||Protein Deficiency*||Gene**|
|Type C||Acetylcoenzyme A:α-glucosaminide-N-acetyltransferase||HGSNAT|
*Meikle PJ, Hopwood JJ, Clague AE, Carey WF (January 1999). “Prevalence of lysosomal storage disorders”. JAMA. 281 (3): 249–54. doi:10.1001/jama.281.3.249. PMID 9918480. https://pubmed.ncbi.nlm.nih.gov/9918480/
Epidemiology of Sanfilippo SyndromeFind out about the population of children with Sanfilippo Syndrome.
Symptoms of Sanfilippo
Children with MPS III generally do not display overt features of the condition at birth. Signs and symptoms of the disease typically begin to be recognized in early childhood, between 2- to 6-years-old, when the child starts missing developmental milestones.
The American Acedemy of Pediatrics suggests considering evaluation for inborn errors of metabolism (including MPS disorders) in children with neuromotor and global developmental delays.
MPS III children have significant behavioral features also seen in ADHD, oppositional behavior, speech/developmental delay, or autism. Children often carry these diagnoses for many years before the underlying diagnosis of Sanfilippo Syndrome is discovered.
Learn about the diagnostic tools for determining whether a patient is positive for Sanfilippo Syndrome.