Mucopolysaccharidosis Type III (MPS III) a.k.a. Sanfilippo Syndrome
What is MPS III (Sanfilippo syndrome)?
MPS III or Sanfilippo syndrome is a mucopolysaccharide disease in which the body has a deficiency of one of the enzymes needed to break down long chains of sugar molecules called glycosaminoglycans (or mucopolysaccharides). High concentrations of mucopolysaccharides in the central nervous system’s cells cause the neurological and developmental problems of MPS III.
There are 4 main types of Sanfilippo syndrome:
- Sanfilippo type A: the most severe form, does not have a normal heparan N-sulfatase enzyme.
- Sanfilippo type B: missing or does not produce enough alpha-N-acetylglucosaminidase
- Sanfilippo C: missing or does not produce enough acetyl-CoAlpha-glucosaminide acetyltransferase
- Sanfilippo D: missing or does not produce enough N-acetylglucosamine 6-sulfatase
What are the symptoms of MPS III (Sanfilippo syndrome)?
Symptoms often appear one year after birth, but between the ages of 2 and 6 is when there is a significant decline in learning ability. General symptoms include:
- Developmental issues
- Behavioral and personality issues
- Coarse facial features
- Sleep difficulties
- Stiff joints that may not extend fully
- Walking problems
What causes MPS III (Sanfilippo syndrome)?
Sanfilippo syndrome is an inherited condition, passed as an autosomal recessive trait.
As explained above, MPS III occurs when the enzymes needed to break down the heparan sulfate sugar chain are missing or defective.
How is MPS III (Sanfilippo syndrome) diagnosed?
The following are all ways that doctors may diagnose MPS III:
- Urine test to measure mucopolysaccharides
- Blood or skin sample to measure enzyme activity
- Genetic testing
What are the treatments for MPS III (Sanfilippo syndrome)?
There is no cure for any of the mucopolysaccharide diseases at this time.
Although enzyme replacement therapy (ERT) has been approved by the FDA for several of the MPS diseases, it has not been shown to be effective in MPS III.