Niemann-Pick disease type A

What else is it called?

  • Acid Sphingomyelinase Deficiency (ASMD type A)
  • Lipid histiocytosis
  • Neuronal cholesterol lipidosis
  • Neuronal lipidosis
  • NPD
  • Sphingomyelin lipidosis
  • Sphingomyelin/cholesterol lipidosis
  • Sphingomyelinase deficiency

Get in touch

Contact our caring team on 08452 412 173 for help and support. Our phone lines open 10am-4pm, Monday to Friday.

Prefer to email? Our email address is contact@metabolicsupportuk.org.

What causes it?

Niemann-pick disease type A (ASMD NP- A) is an inherited lysosomal storage disorder. This disorder affects your child’s bodies inability to break down or store fat within the cells of your body. This disorder can occur in regions of the body such as, the brain, spleen, liver and lungs. ASMD NP- A is caused by an error to one of the inherited genes the child receives from your parents, this gene is called the SMPD1 gene. This gene usually functions to make the substance acid sphingomyelinase which allows you to break down and store fat in your body’s cells.

This condition usually appears during infancy and sadly many infants diagnosed with ASMD NP- A do not survive past the age of 3.

How common is it?

Currently, reports suggest that this condition affects 1 in 250,000 individuals. This condition is more common in the Ashkenazi Jewish populations, where it is estimated to effect 1 – 40,000 people. There is no current indication that this metabolic condition is more common in males than it is females.

What are the signs and symptoms?

Signs and symptoms of ASMD NP- A to look out for include:

  • Cherry red spot in the centre of the eye
  • Feeding problems
  • Neurological disorders (such as loss of reflexes and reaction time)
  • Swelling of the abdomen
  • Yellow like skin (Jaundice)
  • Unexpected growth rate
  • Uncontrolled muscular movement (Athetosis)
  • Swollen lymph nodes

If your child is diagnosed with NPD, they may also develop a large liver and spleen, this is otherwise known as hepatosplenomegaly.

How is it diagnosed?

Genetic sequence testing may also be performed to determine whether your child is a carrier of the metabolic condition. You can be tested at 11 weeks of pregnancy and will get diagnosis or all clear by about 13 weeks, allowing you to make decisions about how to proceed.  If you prefer not to have this test then new-born screening can be carried out.

Bone marrow testing can be performed on your child to test for the levels of ASM in your white blood cells. White blood cells are primarily developed within the bone marrow so low or absent levels of ASM in the white blood cells of the bone marrow would be a good indication of Niemann pick type A disease. However, it is worth noting that this diagnosis is not routinely carried out and diagnosis will most likely be made through genetic testing.

ASMD NP- A can also be diagnosed by taking a skin biopsy. This test involves a health care professional taking a small sample of your skin to measure how the cells move and store components in your child’s body.

Other tests may include an eye exam by an ophthalmologist, identifying a cherry red spot within the eye may be an indicator for Nieman pick type A disease although genetic testing would need to be performed in conjunction with this for the correct diagnosis.

Can it be treated?

Unfortunately, there is no effective treatment for ASMD NP- A. Supportive care is recommended for this condition. This may be from a physical therapy and multi-sensory inclusion team including sensory stimulation to alleviate symptoms such as muscle stiffness. If you have anymore questions regarding the management of this condition, do not hesitate to contact your metabolic consultant and local paediatrician, as they will be able to suggest and input methods of management. Nieman pick type 1 is a progressive condition, so they earlier the intervention the better.

Do my family need to be tested?

ASMD NP- A can only be passed on to a child if both parents have a copy of the faulty gene. This is called autosomal recessive inheritance. A person who has a copy of the faulty gene is known as a carrier.

If both parents are carriers, their child has a one in four (25%) chance of inheriting the disorder, and a one in two chance (50%) of being a carrier. This is the same for each child the parents have.

If the child only inherits one copy of the faulty gene, they will be a carrier but will not have the disorder. In some rare cases, carriers have had mild symptoms of the disorder for which they carry the faulty gene.

Once your child is diagnosed, you can speak to a genetic counsellor. They can explain how you may have inherited NPD. They can also tell you about genetic testing for the rest of your family. They can provide advice and support if you go on to have children of your own. If you have previously had a child with ASMD NP- A and go on to have further children, their New-born Screening test should be carried out within 24-48 hours of birth.

Relevant Organisations

References

References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing helen@metabolicsupportuk.org [Resource Library No: NLY055].

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