The syndrome

Sanfilippo syndrome or type III mucopolisaccaridosis is a rare hereditary neuro-metabolic disease, that is, a genetic error of metabolism.

Mucopolisaccarids are long chains of sugar molecules, which are used in the construction of connective tissues.

When the body has finished using these molecules, it breaks them with enzymes, then recycles them or eliminates them. Children with Sanfilippo syndrome lack or lack the enzyme that serves to break down these molecules, so the body stores them.

This deposit causes progressive damage in different tissues, leading to a general impairment of all vital functions of the organism; in particular, the accumulation of these molecules in the brain leads to progressive intellectual disability and loss of motor function.

There are four different types of Sanfilippo syndrome.
Each type is named according to the missing or defective enzyme type.


Sanfilippo type A

It is the most common type and is also considered the most severe,with death earlier than other types. These children are deficient in the heparan N-sulfatase enzyme.

Sanfilippo type B

It is the result of a lack of

Sanfilippo type C

It is caused by a deficiency of acetyl-CoAlpha-glucosaminid acetyltransferase.

Sanfilippo type D

It is caused by a deficiency of N-acetylglucosamine 6-sulfatamine

It is an autosomal recessive hereditary disease,meaning that both parents must be carriers for the child to be affected.

There is one in two odds (50%) that carrier parents have healthy children who are also carriers. While the probability of carrier parents having healthy non-carrier babies is one in four (25%). One in four cases (25%) it is also the probability that bearer parents have sick children.

Sanfilippo syndrome is a progressive disease: at birth children appear normal and show no signs of the disorder. The onset of the disease occurs around 2-4 years of age, with a symptoms represented by: behavioral disorders (hypercinesia, aggression) and mental deterioration, sleep disorders, very mild dysmorphisms.

Depending on the forms of Sanfilippo, neurological degeneration occurs long before the age of 10 often with loss of intellectual abilities acquired in the very early years.

The most severe form is IIIA, although some patients with attenuated forms have been described. The IIIB and IIID forms are the most heterogeneous as manifestations, while the IIIC form is intermediate to the latter.

Support the research

At the moment for our children there is no cure, but only small gimmicks to try to live with the symptoms of the disease. But one very important thing to believe in is research. Help us too, it takes little.


Our association supports scientific research and is close to families who face Sanfilippo syndrome every day.
Find out what projects we are carrying out; and if you have ideas, we’re listening.