Niemann-Pick Disease

Niemann-Pick disease is a health condition affecting children from birth. People with the disease have changes in their genes that prevent them from breaking down and using fats such as lipids and cholesterol. The excess of these fats in the body prevents the cells from functioning as normal, impacting many organs including the brain, lungs, liver and spleen. It is a genetic condition inherited from parents, where both parents have the recessive gene. This condition impacts an estimated 1 in 90,000 people.

What is Niemann-Pick Disease:

Niemann-Pick disease is a group of rare genetic conditions where there are changes in the specific genes required for the body to break down and use fats. The changes in these genes results in an excess of these fats within the body and cells of the individual. There are 3 types of Niemann-Pick disease; Niemann-Pick disease type A, Niemann-Pick disease type B and Niemann-Pick disease type C.

Symptoms can differ widely by the type of Niemann-Pick disease and the severity of the condition. Symptoms of Niemann-Pick disease may include:

• Loss of muscle control (clumsiness and walking problems)
• Muscle weakness and floppiness
• Stiff and awkward movements
• Vision problems (loss of vision and uncontrolled eye movements)
• Hearing loss
• Sensitivity to touch
• Problems sleeping
• Problems swallowing and eating
• Slurred speech
• Learning and memory problems
• Mental health conditions (including depression, paranoia, behavioural problems)
• Liver and spleen enlargement
• Repeated infections that cause pneumonia

Niemann-Pick disease type A:

This is caused by variation in the SMPD1 gene. This condition is also referred to as acid sphingomyelinase deficiency (ASMD).

Changes in this gene cause the enzyme sphingomyelinase to be missing or to function poorly. This enzyme plays an important role in the break down and use of lipids called sphingomyelin. When these lipids are not broken down the fats build up inside the cell causing damage and overtime resulting in cell death.

Niemann-Pick disease type A is the most severe form and begins in infancy and it has no cure. Most children do not live past a few years of age.

Symptoms of Niemann-Pick type A:

Symptoms of Niemann-Pick disease type A include:

• Liver becoming too large
• Severe brain damage
• Nerve loss that worsens over time

Niemann-Pick disease type B:

This is caused by variation in the SMPD1 gene. This condition is also referred to as acid sphingomyelinase deficiency (ASMD).

Changes in this gene cause the enzyme sphingomyelinase to be missing or to function poorly. This enzyme plays an important role in the break down and use of lipids called sphingomyelin. When these lipids are not broken down the fats build up inside the cell causing damage and overtime resulting in cell death.

Niemann-Pick disease type B is also referred to as juvenile-onset Niemann-Pick disease. It usually presents in later childhood and does not involve damage to the brain. Most people with Niemann-pick type B can live into adulthood, however symptoms impacting organs including the liver and lung can worsen overtime.

Symptoms of Niemann-Pick type B:

Symptoms of Niemann-Pick disease type B include:

• Nerve pain
• Problems walking
• Vision problems
• Liver becoming too large
• Spleen becoming too large
• Lung problems

Niemann-Pick disease type C:

It is caused by variations in the NPC1 and NPC2 genes. Changes to these genes impact the body’s ability to produce the proteins needed to transport, move and use cholesterol and lipids found in cells. Without the ability to move cholesterol and lipids within cells, they build up within the cells of the liver, spleen and lungs. Over time, this excess of lipids and cholesterol impacts the nerves and the brain. Onset of Niemann-Pick disease type C can occur at any age and worsen overtime.

Symptoms of Niemann-Pick type C:

Symptoms of Niemann-Pick disease type C include:

• Abnormal with eye movement
• Difficulty with coordinating movement and with walking
• Difficulty with swallowing
• Problems with hearing
• Poor muscle tone
• Problems with thinking
• Enlargement of spleen and liver
• Frequent respiratory infections

Niemann-Pick Disease Treatment and Support:

There is no cure for Niemann-Pick Disease. However, supportive care is available to manage symptoms. Supportive care available includes:

• Medicines
• Speech therapy
• Physical therapy
• Occupational therapy
• Nutrition therapy
• Oxygen therapy
• Treatment of symptoms

Diagnosing Niemann-Pick Disease:

Diagnosis of the disease begins with a physical exam. The diagnostic test for this condition is dependent on the type of Niemann-Pick disease.

Type A or B can be diagnosed via a blood or skin test that measures the amount of Sphingomyelinase present in the white blood cells.
Type C can be diagnosed by measuring the level of oxysterol cholesterol present in a blood sample.
Other testing may be ordered in the diagnosis of Niemann-Pick disease. This can include:

• Genetic testing
• Magnetic resonance imaging (MRI)
• Eye exam
• Prenatal testing

Prospective parents can undertake carrier screening testing to determine if they carry the condition, this can be conducted by cheek swab testing.

For more information, head to:
https://www.npcd.org.au/