Niemann-Pick is a rare, inherited disease that affects the body's ability to metabolize fat (cholesterol and lipids) within cells. These cells malfunction and, over time, die. Niemann-Pick disease can affect the brain, nerves, liver, spleen, bone marrow and, in severe cases, lungs.

People with this condition experience symptoms related to progressive loss of function of nerves, the brain and other organs.

Niemann-Pick can occur at any age but mainly affects children. The disease has no known cure and is sometimes fatal. Treatment is focused on helping people live with their symptoms.

Niemann-Pick signs and symptoms may include:

• Clumsiness and difficulty walking
• Excessive muscle contractions (dystonia) or eye movements
• Sleep disturbances
• Difficulty swallowing and eating
• Recurrent pneumonia

The three main types of Niemann-Pick are types A, B and C. The signs and symptoms you experience depend on the type and severity of your condition. Some infants with type A will show signs and symptoms within the first few months of life. Those with type B may not show signs for years and have a better chance of surviving to adulthood. People with type C may not experience any symptoms until adulthood.

When to see a doctor

See your doctor right away if you or your child develops warning signs of Niemann-Pick.

Niemann-Pick is caused by mutations in specific genes related to how the body metabolizes fat (cholesterol and lipids). The Niemann-Pick gene mutations are passed from parents to children in a pattern called autosomal recessive inheritance. This means that both the mother and the father must pass on the defective form of the gene for the child to be affected.

Niemann-Pick is a progressive disease, and there is no cure. It can occur at any age.

Types of Niemann-Pick

Types A and B

Types A and B are caused by a missing or malfunctioning enzyme called sphingomyelinase. This affects the body's ability to metabolize fat (cholesterol and lipids), resulting in a buildup of fat in cells. This causes cell dysfunction and, over time, cell death. Type A occurs mainly in infants, who show severe, progressive brain disease. There is no cure, so most children do not live beyond their first few years. Type B usually occurs later in childhood and is not associated with primary brain disease. Most people affected with type B survive into adulthood.

Type C

Niemann-Pick type C is a rare inherited disease. The genetic mutations of this type cause cholesterol and other fats to accumulate in the liver, spleen or lungs. The brain is eventually affected too.

Diagnosis of Niemann-Pick disease begins with a thorough physical exam, which can show an early warning sign such as an enlarged liver or spleen. Your doctor will also take a detailed medical history and discuss symptoms and family health history. Niemann-Pick disease is rare, and its symptoms can be confused with other diseases. Diagnostic techniques depend on the type of Niemann-Pick disease.

• Type A or B. Using a blood or skin sample (biopsy), experts measure how much sphingomyelinase is in white blood cells to confirm the diagnosis.
• Type C. Experts take a small sample of skin to test for Niemann-Pick to assess how the cells move and store cholesterol.

Other tests also may be done, such as:

• Magnetic resonance imaging (MRI). An MRI of the brain may show loss of brain cells. But in the early stages of Niemann-Pick, an MRI may be normal because symptoms typically occur before the loss of brain cells.
• Eye exam. An eye exam can show signs that may be an indication of Niemann-Pick disease, such as eye movement difficulties.
• Genetic testing. DNA testing of a blood sample may show the specific abnormal genes that cause Niemann-Pick types A, B and C. DNA tests can show who the carriers are for all types of Niemann-Pick disease if the mutations have been described in the first person identified in a family (the index case).
• Prenatal testing. Ultrasound can detect the enlarged liver and spleen that's caused by type C. And amniocentesis or chorionic villus sampling may be used to confirm a diagnosis of Niemann-Pick.

No cure exists for Niemann-Pick disease. No effective treatment is available to people with type A or B. For people with mild to moderate type C, a drug called miglustat (Zavesca) may be an option. An international study of 92 people with type C Niemann-Pick showed improved neurological symptoms after taking miglustat regularly for an average of two years.

Physical therapy is an important part of treatment to help maintain mobility as long as possible. People with Niemann-Pick disease need to see their doctors regularly, because the disease progresses and symptoms worsen.