Fatty acid oxidation disorders are rare inherited metabolic disorders in which there is a dysfunction in the oxidation of fatty acids.  This is caused by multiple enzymes who do not properly function, preventing fatty acids from being broken down properly in the cells. 

Fatty acid oxidation disorders can be distinguished in different types. Which type of the disease a patient has, depends on which enzyme is missing or not working properly. 

Different types of fatty acid oxidations disorders are:

• OCTN2 (Primary carnitine deficiency)
• CPT1 (Carnitine palmitoyltransferase 1 deficiency)
• CPT2 (Carnitine palmitoyltransferase 2 deficiency)
• CACT (Carnitine-acylcarnitine translocase deficiency)
• VLCAD (Very long-chain acyl-CoA dehydrogenase deficiency)
• MCAD (Medium-chain acyl-coenzyme A dehydrogenase deficiency)
• MAD (Multiple acyl-CoA dehydrogenase deficiency)
• LCHAD/ MTP (Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency / Mitochondrial trifunctional protein deficiency)

Fatty acid oxidations disorders have an estimated incidence of one in every 5000 to 10,000 live births. The exact prevalence differs per type. For example, the incidence of MCAD is one in every 20,000 births. On a annual basis, 15 to 20 children are born with MCAD in the Netherlands. 

Due to an error in the hereditary material (DNA), patients with a fatty acid oxidation disorder are missing a certain enzyme that prevents fatty acids from being broken down properly in the cells. As a result, the body will not be able to oxidize the fatty acids to make energy and the body will build up toxins.   

The symptoms and the effects of fatty acid oxidations disorders differ per type. The main symptoms are: 

• Low blood sugar level
• Liver problems
• Heart problems such as cardiac arrhythmia
• Muscle pain / breakdown of muscle tissue

In the Netherlands all newborns are being screened for 4 types of fatty acid oxidation disorders: 

• MCAD
• VLCHAD
• LCHAD / MTP
• CPT1

Although newborns are not screened for OCTN-2 deficiency, it is possible to detect this type as an incidental finding. The levels of carnitine are measured in the newborn screening. A low level of carnitine in the blood, could indicate OCTN-2 deficiency.  

Other tests to diagnose a fatty acid oxidation disorder are: 

• Skin biopsy
• Genetic testing 

Unfortunately, there is no cure for fatty acid oxidation disorders. The treatment will depend on the type of the disease. A possible way of treatment is consuming a low fat diet. Your main practicioner will discuss the best treatment options.  

Children with a fatty acid oxidation disorder are seen by a metabolic pediatrician until they reach the age of 18 years old. After this age patients are transferred to the metabolic internist. A possible way of treatment is following a low fat diet. Therefore, your main practinioner works closely with a metabolic dietician. 

Please visit our team page to read more about our specialists.