Fatty Oxidation Disorder (FOD)

What is fatty oxidation disorder?

The term fatty oxidation disorder, often abbreviated FOD, broadly applies to a classification of metabolic deficiencies in which the body cannot breakdown fatty acids in order to produce energy. Known FODs include:

• Carnitine Transport Defect (Primary Carnitine Deficiency)
• Carnitine-Acylcarnitine Translocase (CACT) Deficiency
• Carnitine Palmitoyl Transferase I & II (CPT I & II) Deficiency
• Very Long Chain Acyl-CoA Dehydrogenase (VLCAD) Deficiency
• Long Chain 3-Hydroxyacyl-CoA Dehydrogenase (LCHAD) Deficiency
• Trifunctional Protein (TFP) Deficiency
• Medium Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency
• 2,4 Dienoyl-CoA Reductase Deficiency
• Short Chain Acyl-CoA Dehydrogenase (SCAD) Deficiency
• Short Chain L-3-Hydroxyacyl-CoA Dehydrogenase (SCHAD) Deficiency (now called 3-Hydroxy Acyl       CoA Dehydrogenase Deficiency HADH)
• Electron Transfer Flavoprotein (ETF) Dehydrogenase Deficiency (GAII & MADD)
• 3-Hydroxy-3 Methylglutaryl-CoA Lyase (HMG) Deficiency

What are the symptoms of fatty oxidation disorder?

FODs typically occur in babies, or young children. They may also occur in adults, but this incidence is much more uncommon. Specific signs and symptoms are variable depending on the specific FOD an individual has, and even within family groups, different individuals may present with different symptoms. Some common symptoms across FODs include:

• changes in behavior
• diarrhea, nausea, vomiting
• drowsiness
• fever
• poor mood/fussiness
• diminished or absent appetite
• loss of feeling in arms, or legs
• low blood sugar
• pain, cramps, or weakness in muscles
• vision problems

If left untreated, FODs can cause complications such as:

• anemia
• brain damage
• breathing difficulties
• coma
• heart, live, and lung dysfunction
• intellectual and developmental disability/delay
• seizure

What causes fatty oxidation disorder?

Exact cause of an FOD will depend upon the specific form of disorder a person has. Generally, a FOD is caused by the absence or improper unction of an enzyme responsible for the oxidation of fatty acids. Without the ability to breakdown these compounds, the body is unable to maintain a stable amount of energy. 

How is fatty oxidation disorder diagnosed?

Monitoring blood levels of glucose, ammonia, liver enzyme, and cp(cpk) can all be helpful in determining the presence of an FOD. Newborn screening is highly recommended to detect FODs early, or if you suspect your child may be at risk. Newborn screening includes blood tests, hearing screening, and heart screening.

What are the treatments for fatty oxidation disorder?

Treatment options for FODs are dependent on a proper diagnosis of a specific disorder. Treatments often include careful dieting, addition of necessary enzymes or proteins through prescribed drugs or recommended supplements, and monitoring of symptoms and blood levels. Given an early, appropriate diagnosis, people with FODs often experience healthy and full lives. 

Where can I find out more about fatty oxidation disorder?

• FOD Support Organization
• March of Dimes
• Newborn Screening