Sanfilippo Syndrome: What’s the Life Expectancy For This Rare Genetic Condition?

What Is Sanfilippo Syndrome

Raising a child with Sanfilippo Syndrome can be a significant challenge. With only 1 in 70,000 children born with this condition, questions about prognosis and life expectancy are common.

By understanding Sanfilippo Syndrome and how it affects the body, you can better plan for your child’s future and make the most of every moment.

What Is Sanfilippo Syndrome (MPS III)?

According to the National Organization for Rare Disorders, Mucopolysaccharidosis type III (MPS III) or Sanfilippo Syndrome is a rare genetic condition that causes progressive degenerative effects on the brain and central nervous system. 

Many consider this condition childhood dementia.

MPS III is caused by a lack of an enzyme that breaks down and recycles Heparan Sulphate, a large, complex sugar molecule. As a result, these sugar molecules accumulate and lead to damage to the cells present in the central nervous system, including the brain.

This condition is classified as one of several Mucopolysaccharidoses (MPS), which are part of a larger group of disorders known as Lysosomal Storage Disorders.

Unfortunately, all MPS III conditions cause mental deterioration and four Sanfilippo Syndrome types are present due to mutations in a different gene.

Sanfilippo syndrome type A

This is the most common and most severe subtype of the condition. This subtype is caused by a mutation in the SGSH gene, resulting in a deficiency of the enzyme heparan N-sulfatase.

Sanfilippo syndrome type B

This subtype is characterized by a mutation in the NAGLU gene, which causes a deficiency of alpha-N-acetylglucosaminidase. In some countries in Southern Europe, type B is more prevalent.

Sanfilippo syndrome type C

A mutation in the HGSNAT gene leads to a deficiency of the heparan-alpha-glucosaminide N-acetyltransferase enzyme, which indicates this subtype. It represents 1 in 1.5 million cases.

Sanfilippo syndrome type D

This subtype is characterized by a mutation in the GNS gene, which causes a deficiency of the N-acetylglucosamine 6-sulfatase.

When Does Sanfilippo Syndrome Start?

Children with Sanfilippo Syndrome are born with the condition, but symptoms do not typically appear until the third year of life or beyond.

In the early stages, Sanfilippo children usually develop and reach all their developmental skills on time. However, as the disease progresses, severe symptoms show, and they begin to lose their acquired skills.

What Are the Signs and Symptoms of Sanfilippo Syndrome?

Early symptoms of Sanfilippo syndrome can be challenging because they are often subtle. In the early stages, your child may show specific symptoms such as:

  • Exhibit hyperactivity
  • Have distinctive facial features
  • Get stiff joints
  • Experience sleep difficulties
  • Get speech delays

Sanfilippo Syndrome symptoms are often classified into three primary stages based on their effects.

Stage 1: Early Childhood Stage

The first signs of Sanfilippo Syndrome are often cognitive. Children ages 1-4 years may show signs of delay in development, such as trouble speaking in sentences or having a hard time learning new words. Other symptoms may include frequent nose, ear, or throat infections.

Stage 2: Middle Childhood Stage

As Sanfilippo Syndrome progresses, behavioral problems may become more pronounced. A child in ages 3-5 years old may become aggressive, behave impulsively, or have sleeping problems. As the condition worsens, they may also experience a progressive decline in cognitive function and lose the ability to speak.

Stage 3: Late Childhood

During this stage, most children with Sanfilippo Syndrome often experience movement disorders. They may become less coordinated and have difficulty walking. In addition, they may suffer from seizures, disordered sleep, and vision or hearing loss.

@love_logan07 Sanfilippo Syndrome strips away every skill children have gained early on in life until it takes their life. There is no treatment or cure. #sanfilippo #lovelogan #skills #loss #speech ♬ Je te laisserai des mots – Patrick Watson

How To Test for Sanfilippo Syndrome

Diagnosing Sanfilippo syndrome can be complex because its symptoms are similar to other conditions. To confirm a diagnosis, doctors often rely on a combination of tests. These tests include:

Genetic testing

This test requires a blood or saliva sample. It checks for congenital anomalies and mutations in genes associated with the condition.

Urine testing

The urine test looks explicitly for increased glycosaminoglycans (GAGs), a carbohydrate type, and certain molecules, such as heparan sulfate, keratan sulfate, and dermatan sulfate.

Blood testing

A blood test determines the level of enzymes in the blood. A deficiency of certain enzymes may indicate Sanfilippo syndrome. This test is recommended for infants and young children because they may be unable to provide a usable urine sample.

Supplemental newborn screening

Parents can also opt for supplemental screening for their newborns. Although it is not an MPS III-specific test, this screen can help identify babies with early diagnosis of abnormal conditions.

What Is the Life Expectancy of a Child With Sanfilippo?

Questions about how long someone can live with Sanfilippo Syndrome are often difficult for doctors to answer. The severity of the condition can vary significantly from person to person, making it hard to make generalizations.

But although it varies with each subtype, the mortality rate for Sanfilippo syndrome is high. A person with Sanfilippo syndrome often reaches a life expectancy of up to three decades. 

According to a 2017 study, people with MPS III type A have a mean expectancy of 11 to 19 years. Those with types B and C have a longer life expectancy, which ranges from 11 to 34 years. 

For type D, life expectancy is likely to extend into adolescence or early adulthood.

What Are the Treatments for Sanfilippo Syndrome?

Like most genetic conditions, there is currently no cure for Sanfilippo syndrome. However, scientists are working hard to develop new treatments.

The most promising treatment options for Sanfilippo syndrome are gene therapy and enzyme replacement therapy (ERT). It involves replacing the missing or defective enzyme with a working one, to improve quality of life.

However, most clinical trials are still in the early stages. So far, they have only been conducted on animals. More research is needed to determine if these treatments are safe and effective for humans.

How Can Parents Support Children With This Rare Disease?

If your child has been diagnosed with Sanfilippo syndrome, it is important to seek support from friends, family, and other people in the community. 

Many organizations can help you connect with others who understand what you are going through.

The MPS Society is an excellent place to start. This organization offers support and resources for families affected by MPS disorders. They also fund research to find new treatments and a cure for these conditions.

You can also join the Cure Sanfilippo Foundation, a nonprofit organization that funds research and raises awareness about this rare disease. The foundation also provides quality of life and mental health support for families affected by Sanfilippo syndrome.

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