Long Chain 3 Hydroxyacyl CoA Dehydrogenase Deficiency

What else is it called?

  • LCHAD Deficiency

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What causes it?

This condition is grouped with the defects known as Fatty Acid Oxidation Disorders (FOD’s). Fat or adipose tissue is the main energy store of our bodies. It is derived not only from the fat that you eat, but also made in the body from any excess calories obtained from your food and drink. When fat is broken down it releases fatty acids. When you eat, regular carbohydrate containing meals, your body uses the sugar in the meals as an energy source and does not use much fat.

When your body needs more energy, it needs to break down fat quickly. This happens especially if you are ill or if you go without food for a long time. In LCHADD, the fat is only partially broken down and therefore your body can not make enough energy quick enough for your body to use it. This leads to a lack of energy and a build-up of toxic substances in your body which come from the partially broken-down fat.

How common is it?

We do not know how many people are affected by LCHADD. It is estimated that worldwide this condition affects 1 in every 250,000 people. There is a higher prevalence in Baltic countries. A study in Finland estimated that approximately 1 person in every 62,000 were affected.

What are the signs and symptoms?

Signs and symptoms of LCHAD deficiency usually appear during infancy or early childhood. You may have symptoms including:

  • feeding difficulties
  • lack of energy (lethargy)
  • low blood sugar (hypoglycaemia)
  • weak muscle tone (hypotonia), the child may appear to be ‘floppy’
  • liver problems
  • abnormalities in the light-sensitive tissue at the back of the eye (retina)

Later in childhood, the following symptoms may occur:

  • muscle pain
  • breakdown of muscle tissue
  • a loss of sensation in your arms and legs (peripheral neuropathy).

This condition is usually most severe during the first year of life. Symptoms are usually triggered when you have gone for long periods without food, if you have a viral infection, or if the body is under other such stresses.

In rare cases, LCHADD is associated with sudden cardiac arrest or sudden infant death. If you are pregnant with a child who has LCHADD you may develop a rare liver and blood clotting condition called HELLP syndrome.

How is it diagnosed?

LCHADD can be diagnosed through specialised blood and urine tests. Further tests may be needed to confirm the diagnosis. Newborn screening for LCHADD is available in Austria, Czech Republic, Denmark, Germany, Hungary, Iceland, Netherlands and Portugal.

This disorder has signs and symptoms that are exactly the same as Mitochondrial trifunctional protein deficiency (TFPD) so it is likely that this condition will also be considered and will need to be ruled out in diagnosis. It is also sometimes mistaken for Reye syndrome. This is a severe disorder that may develop in children while they appear to be recovering from viral infections.

Can it be treated?

There is no cure for this condition, it is a lifelong condition. If you have this disorder you will need to stick to a strict low-fat diet which has limited amounts of long chain fatty acid intake and substitution with medium chain fatty acids. After you have been diagnosed you will be referred to a specialist dietitian who will plan out your diet and explain everything. You should not make any dietary changes without the prior advice of your dietitian.

You will also need to avoid long periods of time without food and other triggers as this is dangerous and can precipitate symptoms. When you receive your diagnosis you will be given an emergency regimen explaining what to do if you or your child becomes ill. This includes getting bugs such as vomiting, diarrhoea and fever.

If you are unable to tolerate these drinks, continue to be ill and/or develop diarrhoea then you will need to be admitted to hospital to be given appropriate treatment as soon as possible. You will be given an emergency contact number to ring, however if this is unavailable call 999 for an ambulance or go to your nearest hospital’s accident and emergency (A&E) for treatment. If you are in any doubt at all then seek medical attention. Treatment of this condition is lifelong.

Early diagnosis and the correct treatment and management of this disorder is vital.

Do my family need to be tested?

LCHADD 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 LCHADD is inherited. They can also tell you about genetic testing for the rest of your family.

Relevant Organisations


References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing helen@metabolicsupportuk.org [Resource Library No: LFKB03].

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