Carnitine Palmitoyltransferase II Deficiency

What else is it called?

  • Carnitine palmitoyltransferase 2 deficiency
  • CPT II deficiency
  • CPT2 deficiency

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What causes it?

Carnitine Palmitoyltransferase ll Deficiency (CPT2 deficiency) is a condition in which your body is unable to transport certain fats (long chain fatty acids) you consume into your body’s cells to be used for energy. CPT2 deficiency is caused by a genetic defect from the genes you inherit from your parents. The CPT2 gene you inherit from your parents gives your body the ability to be able to transport fat into the cells of your body to be used for energy. Because there is an error with this gene you may either lack the ability to be able to transport these fatty acid chains into your body’s cells or they can only be transported into your cells in small quantities.

There are three subgroups for this condition, these are:

  • The neonatal form
  • The severe form
  • The myopathic form

Of the three different CPT2 deficiency conditions the neonatal form is the least common. The neonatal form is the most lethal form of CPT2 deficiency and is known to be fatal by the age of 1. If you are diagnosed with the severe form CPT2 deficiency the symptoms tend to appear within the ages of 6 to 24 months. The myopathic form, which is the least severe form of CPT2 can present symptoms either in early childhood or adulthoo

How common is it?

Currently 300 cases of this condition have been reported globally. Most people who are diagnosed with CPT2 deficiency are myopathic. CPT2 deficiency can occur in all races and ethnicities. There is no greater risk between males and females.

What are the signs and symptoms?

The three sub categories of CPT2 deficiency present very different signs and symptoms:

The Neonatal form – onset soon after birth:

  • Difficulty breathing
  • Seizures
  • Irregular heart beats
  • Liver failure
  • Abnormalities associated with the brain and kidneys
  • Low blood sugars and low level of ketones (hypoketotic hypoglycemia)
  • Facial abnormalities

The Severe form – onset usually within the first year of life:

  • Muscle pain and weakness
  • Seizures
  • Enlarged liver (hepatomegaly)
  • Liver failure
  • Recurring episodes of hypoketotic hypoglycemia
  • Irregular heart beats

This form of CPT 2 deficiency may be triggered by periods of fasting or by illnesses such as viral infections. Prognosis includes:

  • Risk for liver failure
  • Nervous system damage
  • Coma
  • Sudden death

The Myopathic form – onset of first episodes presents during childhood and adolescence:

  • Recurrent episodes of muscle pain, stiffness and weakness
  • Breakdown of muscle tissue (rhabdomyolysis)
  • Brown urine/ coca-cola coloured urine (an indication of protein in the urine)
  • Kidney failure
  • Difficulty breathing

Stress, exercise, exposure to extreme temperatures, infections or fasting can trigger episodes of muscle pain and breakdown of muscle tissue. This variant is asymptomatic between episodes.

How is it diagnosed?

CPT2 deficiency is diagnosed through the new born screening test. Health care professionals can perform genetic tests on your family to determine whether they are a carrier for the disorder. These tests can also be carried out during pregnancy to see if the child is CPT2 deficiency, this genetic testing is beneficial for when the baby is born so management for CPT2 deficiency can commence promptly.

CPT2 can be a very difficult metabolic condition to diagnose, as symptoms of the myopathic form of this condition generally present in adulthood without symptoms of heart problems, only fever, difficulty breathing, fatigue and dark coloured urine. Your doctor may also conduct a special blood test called tandem mass spectrometry of serum/plasma acylcarnitines or tests to measure enzymatic activity.

Can it be treated?

Currently there is no treatment for CPT2, you can live a perfectly healthy life with the correct management of this condition. Symptoms of this disorder tend to be patient specific but generally the ways you can manage CPT2 deficiency are by:

  • Avoiding long durations of physical activity
  • Avoiding prolonged fasting and high carbohydrate low fat diets.
  • Avoiding known triggers
  • Supplement the body with Carnitine
  • Sufficient hydration
  • If necessary, dialysis must be performed immediately

For diet, you should consult specialised dietician. However, it is generally recommended to consume foods containing small or no amount of long-chain fatty acids, some of the suggested foods that should be avoided are:

  • Coconut oil
  • Sunflower oil
  • Dairy
  • Lamb

High-carbohydrate (70%) and low-fat (<20%) diet and supplementation of glucose during infections are recommended.

Do my family need to be tested?

CPT2 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 CPT2. 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.

Diagram showing the autosomal recessive inheritance pattern.

Relevant Organisations


References are available on request. Please contact us by phoning 0845 241 2173 or emailing [Resource Library No CFKB09:].

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