Sanfilippo Syndrome in Children

Sanfilippo syndrome is known as infantile Alzheimer's. Find out what this rare disease involves and where it gets its name.

Sanfilippo syndrome, also known as mucopolysaccharidosis type III (MPS III), is a rare genetic disease that most of the population’s unaware of. For this reason, and to give visibility to people suffering from this syndrome, we’ve decided to write the following article.

Pediatrician Sylvester Sanfilippo first discovered this rare disease in the 1960s and gave the syndrome its name. Do you want to know why it occurs, what its characteristics are, and what possible treatment looks like? Pay attention to what we’ll explain below.

Sanfilippo syndrome in children

Sanfilippo syndrome affects only 1 in 70,000 births. It’s a rare disease that involves the severe and slowly progressive degeneration of the central nervous system. As a result, the psychomotor and cognitive development of children with this syndrome suffer greatly.

The cause that explains the appearance of Sanfilippo syndrome is the presence of deficiencies in one of the four enzymes that participate in the degradation of heparan sulfate. This results in the accumulation of mucopolysaccharides (long chains of sugar molecules) in the cells, affecting the correct functioning of the organism.

Depending on the gene affected and the enzyme it produces, four types of Sanfilippo syndrome exist:

• Type A: In this case, there are alterations in the production of the enzyme Heparan N-sulfatase as a result of a defect in the SGSH gene. This is the type of Sanfilippo syndrome with the most severe symptoms.
• Type B: When there are deficiencies in the enzyme N-acetylglucosaminidase as a result of a defect in the NAGLU gene.
• Type C: In this case, there are abnormalities in the production of the enzyme alpha-glucosaminide N-acetyltransferase
  caused by a defect in the HGSNAT gene.
• Type D: Here, there’s insufficient or no production of N-acetylglucosamine-6-sulfatase due to a defect in the GNS gene.

The involvement of any of these genes is inherited from both parents. In other words, it’s an autosomal recessive inherited disease. This is because both parents, who are healthy carriers of the mutated gene, pass on a copy of the gene to their child.

Most common symptoms

As we’ve seen, there are several types of Sanfilippo syndrome, so this disease encompasses a wide spectrum of symptoms and levels of severity. In general, these symptoms appear between the ages of 2 and 6 years. The most common symptoms are the following:

• Hyperactivity
• Aggressive behaviors
• Problems in psychomotor development
• Thick eyebrows and excess body hair
• Sleep problems
• Inflammation of the liver and spleen
• Loss of hearing and vision
• Chronic diarrhea
• Frequent coughs, colds, and throat infections
• Stiff joints that may not fully extend
• Difficulty controlling their sphincters

In the most severe cases, the following often occurs:

• Presence of epileptic seizures
• Important deterioration of certain intellectual abilities (to read, to adapt to the environment, to relate socially, etc.)
• Progressive loss of motor skills (walking, speaking, eating, etc.)

Treatment of the disease

Presently, there’s no definitive cure for Sanfilippo syndrome. The treatment these children undergo aims to improve their quality of life and alleviate symptoms as much as possible through behavior modification therapy, physiotherapy, and pharmacotherapy.

However, there’s hope that, in the future, more effective treatments can be adopted that will allow the disease to be cured. For example, replacement therapy of the affected enzyme or gene therapy (replacement of the defective gene with a copy of a normal correct gene).

Prognosis of Sanfilippo syndrome

As a neurodegenerative disease, children gradually lose their abilities until they die, most of them in adolescence or, in the most severe cases, during childhood. However, there are also patients with Sanfilippo syndrome who live into adulthood.

Therefore, we can say that the evolution of the disease varies greatly depending on the type of syndrome and its severity.

In any case, we need to fight so that little ones who develop this disease have the happiest and most satisfactory life possible, within their possibilities.