Fatty Acid Oxidation Disorders

Nevada Newborn Screening Program

Newborn Screening For Fatty Acid Oxidation Disorders

Fatty Acid Oxidation Disorders (FAODs) are a group of rare inherited conditions caused by enzymes that do not work properly. A number of enzymes are needed to break down fats in the body (a process called fatty acid oxidation). Problems with any of these enzymes can cause a fatty acid oxidation disorder. People with FAODs cannot properly break down fat either from the food they eat or from fat stored in their bodies. A healthy body uses glucose (sugar) for energy. When the body uses all the glucose it has, it gets energy from fat. A baby with a fatty acid oxidation disorder cannot use fat for energy. This can cause low blood sugar and harmful substances to build up in his/her blood.

FAODs are inherited in an autosomal recessive manner and affect both males and females. This means they are passed from parent to child through genes. Genes are parts of your body's cells that store instructions for the way your body grows and works.

The symptoms and treatment vary between different FAODs. They can also vary from person to person with the same FAOD. See the fact sheets for each specific FAOD.

Frequently Asked Questions

What fatty acid oxidation disorders are tested for in newborn screening?
Carnitine Uptake Defect (CUD)

Children with CUD usually have symptoms between birth and age seven, but some never have symptoms. If untreated, CUD can cause brain damage or death. CUD affects one out of every 100,000 babies each year in the United States. However, it is more common in certain populations. It is estimated to affect one out of every 40,000 babies born in Japan.

Long-Chain Hydroxyacyl-COA Dehydrogenase Deficiency (LCHAD)

About one in 75,000 babies is born with LCHAD each year in the United States. Children generally have symptoms shortly after birth. LCHAD may be more common in people from Finland.

Medium-Chain ACYL-COA Dehydrogenase Deficiency (MCAD)

MCAD affects about one in 15,000 babies in the United States. Symptoms most often occur in babies or young children and consist in hypoglycemia (low blood sugar), liver disease or sudden death. It is more common in people of northern European ancestry. If untreated, MCAD can cause brain damage and breathing problems.

Trifunctional Protein Deficiency

TFP is a very rare condition and affects less than one in 100,000 babies is born each year with TFP in the United States. There are three kinds of TFP:

  • Early TFP-babies can have signs and symptoms any time through age 2. If untreated, these babies often die from heart or lung problems by age 3.
  • Childhood TFP-children have signs and symptoms after age one. Repeat TFP symptoms in children can cause brain damage and can lead to learning problems or intellectual disability. Some children with childhood TFP may feel muscle weakness or pain after they exercise hard, they are sick or have some other kind of body stress.
  • Mild TFP-this kind of TPF is rare. Symptoms begin any time after age 2, including as an adult.
Very-Long-Chain ACYL-COA Dehydrogenase Deficiency (VLCAD)

If untreated, VLCAD can cause brain damage and even death. More than one in 75,000 babies is born with VLCAD each year in the United States. There are three kinds of VLCAD:

  • Early VLCAD-baby has symptoms by 4 months of age. About half of all babies with VLCAD have early VLCAD.
  • Childhood VLCAD-symptoms appear closer to a baby's first birthday or in early childhood. About one-third of all people with VLCAD have childhood VLCAD.
  • Adult VLCAD-about 20 percent of with VLCAD have this kind. Symptoms appear in the teen years or adulthood.
Carnitine Palmitoyltransferase I Deficiency (CPT-1A)

CPT-1A is a rare condition. Less than 50 individuals have been reported to have CPT-1A. The condition is more common in certain ethnic groups, including in the Hutterite population of North America and in the Inuit people of Alaska and Canada. CPT-1A is found in one out of every 1,200 babies born in the American Hutterite population.

Carnitine Palmitoyltransferase II Deficiency (CPT-II)

CPT-II is a rare condition. There are three main forms of CPT-II, which differ in their age of onset. The neonatal form has been reported in 18 cases. The form that affects babies and young children has been described in at least 30 cases. Classic CPT-II generally affects adults, and it is the most common form. It has been reported in more than 300 cases. The overall incidence of CPT-II is unknown.

Short-Chain ACYL-COA Dehydrogenase Deficiency (SCAD)

SCAD is estimated to affect one in 40,000 to 100,000 newborns. Most individuals who are identified as having SCAD never experience symptoms.

Glutaric Acidemia, Type II (GA-2)

GA-2 is a very rare condition and the exact number of individuals affected by GA-2 is currently unknown.GA-2 can cause hypoglycemia, weak muscle tone, severe heart problems, and death. GA-2 is a different condition from GA type 1.

What are signs and symptoms of these disorders?

Signs and symptoms of these disorders usually occur in babies or young children. Some of these disorders can first appear in adults, but this is rare. Illness or infection, eating the wrong kinds of foods, or going for a long time without eating can bring about signs and symptoms of these disorders. Signs and symptoms include:

  • Changes in behavior
  • Diarrhea, nausea and throwing up
  • Drowsiness
  • Fever
  • Fussiness
  • Little appetite
  • Loss of feeling in the arms and legs
  • Low blood sugar
  • Muscle pain, cramps or weakness
  • Vision problems
What health problems can these disorders cause?

If not treated, some of these disorders can cause health problems, including:

  • Brain damage
  • Breathing problems
  • Coma
  • Heart, liver and lung problems
  • Intellectual and developmental disabilities
  • Seizures
  • If not treated, some of the disorders can lead to death.

Treatments often recommended for children with fatty acid oxidation disorders include:

  • Avoidance of fasting
  • Dietary treatments-Your baby may need to be on a restricted diet in order to avoid certain foods that his or her body cannot break down. A dietician or a nutritionist can help you plan a healthy diet for your child.
  • Supplements and medications such L-carnitine, MCT oil, riboflavin, glycine, DHA