Alpha-Methylacyl CoA Racemase Deficiency

What else is it called?

  • 2-methylacyl-CoA Racemase Deficiency
  • AMACR Deficiency
  • BASD4
  • Congenital bile acid synthesis defect type 4
  • Liver Disease-Retinitis Pigmentosa-Polyneuropathy-Epilepsy Syndrome

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What causes it?

This is a bile acid synthesis disorder. This means it affects how your body produces bile acids. These acids are made from cholesterol and are found in your liver. They are needed to:

  • Help make sure bile flows around your body
  • Excrete bile from your body
  • Help your intestines absorb fat and fat-soluble vitamins
  • Break down and get rid of cholesterol from your body

If there is a problem making bile acids properly they will build up in your body along with cholesterol and other substances. These then become toxic and cause damage to your organs.

Specifically, this disorder is caused by a problem in the AMACR gene. This gene controls the AMACR enzyme. Your body needs this to break down pristanic acid and molecules that come from it. Pristanic acid comes from the meat and dairy that you eat. When you don’t have enough of this enzyme, the acid builds up in the blood and becomes toxic

How common is it?

We do not know how many people have this disorder. It is very rare with only a small amount of cases that are known. It has been diagnosed in both children and adults. It can affect people from any race or background and affects males and females equally. Collectively the Bile Acid Synthesis Disorders are thought to affect 1 person in every 50,000.

What are the signs and symptoms?

Children may have:

  • Severe fat deficiency

Symptoms of this include the following:

o Dry, scaly rash

o Hair loss

o Loss of hair colour

o Poor wound healing

o Growth restriction in children

o Increased susceptibility to infection

  • Blood in or with the stools
  • Fat soluble vitamin deficiencies

The most common symptoms of these are:

o Night blindness (vitamin A),

o Softening of the bones (vitamin D)

o Nerve and muscle damage, loss of movement and vision difficulties (vitamin E)

o Excessive bleeding and bruising (vitamin K)

  • A reduced bile flow

If your bile is not flowing properly you may notice the following:

o Yellowing of the skin or eyes

o Itching

o Light brown urine

o Fatigue

o No appetite and/or weight loss

o Fever or night sweats

o Abdominal pain

o Greasy or clay-coloured stools

If you are an adult, you may have a condition called Sensory Motor Neuropathy. This affects the nerves and causes symptoms such as strange sensations in the arms and legs, weakness and balance problems. You may have already had a mild liver problem and fat-soluble vitamin deficiency from an early age. You may have had mild symptoms earlier in life or no symptoms at all until the Sensory Motor Neuropathy or other neurological problems began.

Other symptoms may include:

  • A gradual decline in memory and thinking skills
  • Seizures
  • Stroke-like episodes
  • Migraine
  • Sight problem

These symptoms can change, and you may get them at different times. Some people may not get any of them at all. The signs and symptoms can vary greatly between individuals, even within the same family.

How is it diagnosed?

You will be diagnosed after a clinical examination by your specialist or doctor. However, as the signs and symptoms of this disorder are similar to other conditions, you will need further tests. Doctors will analyse your blood, bile and urine using a special test called mass spectrometry. Sometimes they may use exome sequencing, which is becoming more common. You may also have an MRI scan.

Can it be treated?

There is no cure for AMACR Deficiency it can be managed by taking medication to increase the amounts of primary bile acids in the body. You will need to eat less meat and dairy products to reduce the amount of pristanic acid in your body. A dietitian will give you information on the best diet to follow.

Do my family need to be tested?

AMACR Deficiency 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 you are diagnosed, you can speak to a genetic counsellor. They can explain how you may have inherited AMACR Deficiency. 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

Relevant Organisations


References are available on request. Please contact us by phoning 0845 241 2173 or emailing [Resource Library No: APX001].

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