Niemann-Pick disease is a group of rare genetic diseases that cause the buildup of fatty substances in your body. Type C can develop at any time between infancy and adulthood.

Niemann-Pick disease (NPD) is a group of genetic conditions that causes high amounts of fat to build up in your:

NPD has classically been divided into four subtypes called types A, B, C, and E.

NPD type C can occur anywhere between infancy and adulthood. Some people with the disease pass away early in childhood, while others live well into adulthood.

Type C is caused by a mutation in your NPC1 or NPC2genes, which leads to reduced activity of the enzyme acid sphingomyelinase (ASM). Normally, this enzyme breaks down fat molecules into smaller molecules your body can use as energy.

Here, we look at this rare genetic condition in more detail, including symptoms, treatment options, and the outlook for people with it.

NPD type C is a genetic disease caused by a mutation in either your NPC1 or NPC2 genes. In about 95% of people with NPD type C, the mutation is in their NPC1 gene. These mutations cause a fatty substance called cholesterol to build up in tiny structures in cells called lysosomes. The buildup of cholesterol can lead to cellular and organ damage.

NPD type C affects about 1 in 150,000 people and is most common in French-Acadian people in Nova Scotia. But it can occur in people of any ethnic background.

Signs and symptoms of Niemann-Pick type C disease depend on your age of onset. Symptoms related to problems with your internal organs tend to occur most often in people who develop them at a younger age. Neurological and psychiatric symptoms develop slowly over time.

Onset under 2 years

Typical signs and symptoms that occur in those younger than 2 years old include:

Between 2 and 6 years

Children between 2–6 years old may have:

  • low muscle tone (hypotonia)
  • developmental delays
  • trouble moving their eyes in certain ways
  • clumsiness
  • difficulties with coordination (ataxia)

Between 6 and 15 years

People between 6–15 years old may develop:

  • clumsiness
  • ataxia
  • academic difficulties
  • cognitive impairment
  • trouble moving eyes in certain ways
  • seizures
  • involuntary muscle contractions (dystonia)
  • spasticity

A characteristic feature is also gelastic cataplexy, which is a brief episode of loss of muscle tone triggered by laughter that doesn’t cause loss of consciousness.

Adults

Along with neurological symptoms that can onset during childhood, adults may also have:

NPD can lead to potential complications, such as:

How does Niemann-Pick disease type C compare with other types?

People with NPD type A usually have an enlarged spleen and liver in infancy and rarely survive beyond 2–3 years. Type B is usually less severe and typically causes minimal neurological symptoms.

Type E is the rarest version of the disease and develops in adulthood.

NPD type C can onset at any age. It’s important to get medical attention if you notice any cognitive changes or unexplained changes in movement in you or your child.

These changes can have many potential causes, but a doctor or healthcare professional can run tests to help you figure out why they’re occurring.

A doctor will start the diagnostic process by:

  • reviewing your personal and family medical history
  • performing a physical exam
  • asking you about your symptoms

If a doctor suspects you have NPD type A or B, the main test to confirm the diagnosis is a blood test to measure the activity of ASM in your white blood cells and to look for associated gene mutations.

The main diagnostic test for NPD type C is now genetic testing for biomarkers, such as:

  • oxysterols
  • lysosphingolipids
  • bile acids

In some cases, a skin biopsy will be performed. A special stain called filipin will be applied to this skin sample to measure your ASM activity.

You may receive many other tests to monitor complications, such as:

The treatment for NPD type C is mainly supportive. Physical therapy can help improve neurological symptoms and trouble with movement. Pain may be managed with pain relievers.

The medication miglustat (Zavesca) is approved in Europe, Canada, and Japan for type C disease. But it’s not yet Food and Drug Administration (FDA) approved in the United States.

Is the Niemann-Pick disease type C curable?

There’s no cure for NPD. At this time, treatment is mostly supportive.

The outlook for people with NPD type C varies depending on when your symptoms occur. The chances of survival are very poor if symptoms develop in infancy. If it develops after the age of 5 years old, people may live to be older than 20 years old.

Some children develop severe, life threatening complications early, and others have mild symptoms that remain undiagnosed into adulthood. Life expectancy can range anywhere from a few days to over 60 years but is most commonly between 10–25 years of age.

NPD type C is a genetic disease, and there’s no known way to prevent it.

Currently, NPD type C has no cure, and treatment is largely supportive. People with the disease generally have a better outlook when symptoms develop when they’re at an older age.