Niemann-Pick disease type A (neurological type)

The symptoms include:

• hepatosplenomegaly (an enlarged liver and spleen),
• failure to  thrive (gain weight and grow at the expected rate)
• progressive (getting worse over time) deterioration of the nervous system.

Sadly, children affected by this type do not survive past early childhood.

Niemann-Pick disease type B (non-neurological type)

The symptoms include:

• hepatosplenomegaly
• slow growth
• problems with lung function, including frequent lung infections
• blood abnormalities - elevated levels of cholesterol and other lipids, and decreased numbers of platelets (bodies that help blood clot).

People with Niemann-Pick disease type B usually survive into adulthood.

Niemann-Pick disease type C

This usually appears in childhood, the symptoms can include:

• severe liver disease
• breathing difficulties
• developmental delay
• seizures
• dystonia (poor muscle tone)
• lack of coordination
• problems with feeding
• inability to move the eyes vertically.

People with this condition can survive into adulthood. Niemann-Pick disease type C is further subdivided into types C1 and C2, each caused by a different gene change (mutation).

Niemann-Pick type D is a form of Niemann-Pick type C found in a population of Nova Scotia ancestry.

Mutations in the SMPD1 gene cause Niemann-Pick disease types A and B. This gene provides instructions for producing an enzyme called acid sphingomyelinase (ASM). Mutations in either the NPC1 or NPC2 gene cause Niemann-Pick disease type C. The NPC1 gene provides instructions for producing a protein that is involved in the movement of cholesterol and lipids within cells.

Type A and B are diagnosed by measuring the amount of ASM in white blood cells using a blood sample. Testing the DNA to look for the mutation causing types A and B can confirm the diagnosis.

A skin biopsy is usually used to diagnose type C and type D Niemann-Pick disease. Laboratory scientists will watch how the skin cells grow and study how they move and store cholesterol. Testing the DNA to look for the mutation causing type C/D can confirm the diagnosis.

At this time, there is no effective treatment for type A. But supportive therapies can be used to keep the child comfortable and improve their quality of life.

Bone marrow transplantation has been performed on a few patients with type B with fairly good results. Researchers continue to study possible treatments, including enzyme replacement therapy. Trials in humans are now underway in a number of countries, including the UK and USA.

Recently a new treatment called miglustat has been approved for type C. However, medicines are available to control or relieve many symptoms, such as cataplexy and seizures.

There is no specific treatment for type D.

Inheritance patterns
Autosomal recessive pattern of inheritance. Affected families should be referred to a genetic centre for information and support.

Prenatal diagnosis
For types A, B and most forms of type C, this is possible by chorionic villus sampling at ten to twelve weeks or amniocentesis at sixteen weeks.

Niemann-Pick Disease Group (UK)

Tel: 0191 415 0693
Email: niemann-pick@zetnet.co.uk
www.niemann-pick.org.uk

The Group is a Registered Charity in England and Wales No. 1144406. It provides information and support to families affected by all forms of Niemann-Pick disease. It operates a 24 hour telephone helpline and funds a dedicated Clinical Nurse Specialist to give support through advice, counselling, specialist clinics and advocacy. Holds an annual family conference.

Group details last updated October 2015.

Support and information in the UK for metabolic disorders is also available from Climb (see entry Inherited Metabolic diseases).

Support for dementia in Niemann-Pick disease can be obtained from the Alzheimer's Society (see entry Alexander disease).