Organic Acid Metabolic Disorders

Nevada Newborn Screening Program

Newborn Screening For Organic Acid Metabolic Disorders

Organic Acid Disorders (OAs) are a group of rare inherited conditions caused by enzymes that do not work properly. A number of enzymes are needed to process protein from the food we eat for use by the body. Problems with one or more of these enzymes can cause an organic acid disorder. People with organic acid disorders cannot break down protein properly. This causes harmful substances to build up in their blood and urine. These substances can affect health, growth and learning.

The symptoms and treatment vary between different organic acid disorders. They can also vary from person to person with the same organic acid disorder. See the fact sheets for each specific organic acid disorder. Organic acid disorders 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.

Frequently Asked Questions

What organic acid metabolism disorders are tested for in newborn screening?

3-Methylcrotonyl-CoA Carboxylase Deficiency (3MCC): If your baby has 3MCC, his/her body has trouble breaking down the amino acid leucine. All foods with protein have leucine. For people with 3MCC, eating foods with protein can cause health problems. Each year in the United States, more than one in 75,000 babies is born with 3MCC.
Beta-Ketothiolase Deficiency (BKT): If your baby has this disorder, her body cannot use the amino acid isoleucine and cannot use ketones. Less than one in 100,000 babies is born each year in the United States with BKT.
Glutaric Acidemia Type 1 (GA1): If your baby has this condition, his/her body cannot use three amino acids called lysine, hydroxylysine and tryptophan. All foods with protein have these amino acids. For people with GA1, eating foods with protein can cause health problems. Each year in the United States, more than one in 75,000 babies is born with GA1.
Hydroxymethylglutaric Aciduria (HMG): A baby with HMG has trouble breaking down the amino acid leucine. His body also stops making ketones, and he can develop low blood sugar. People with HMG may need to eat foods, like bread, pasta, fruits and vegetables that are high in carbohydrates. They also may need to limit foods that are high in protein and fat. Each year in the United States, less than one in 100,000 babies is born with HMG.
Isovaleric Acidemia (IVA): Like 3MCC, in this condition your baby has trouble breaking down leucine. Each year in the United States, less than 1 in 100,000 babies is born with IVA.
Methylmalonic Acidemia, CBl A and CBl B forms: This disorder causes your baby's body to have trouble breaking down fat in food and four amino acids called isoleucine, methionine, threonine and valine. Less than one in 100,000 babies is born each year in the United States with this disorder.
Methylmalonic Acidemia, Mutase Deficiency Form (MUT): This disorder is similar to Cbl A, B. More than one in 750,000 babies is born each year in the United States with MUT.
Multiple Carboxylase Deficiency (MCD): In MCD, your baby's body cannot use a vitamin called biotin. Biotin is a B vitamin that is in foods like eggs and milk. The body uses biotin when it makes and breaks down proteins, fats and carbohydrates. Less than one in 100,000 babies is born with MCD each year in the United States.
Propionic Acidemia (PROP): Like in Cbl A, B and MUT, your baby's body cannot use the four amino acids isoleucine, methionine, threonine and valine. Eating foods high in protein can cause dangerous substances to build up in the blood. More than one in 75,000 babies is born each year in the United States with PROP.

What are signs and symptoms of these disorders?

Some babies with these kinds of disorders never have serious signs or symptoms. Sometimes signs and symptoms may not happen until later in life, even as a teenager. In addition, signs and symptoms may appear and then go away over time. Each disorder has different signs and symptoms, but they often include:

Dehydration. Signs of dehydration include feeling dizzy or lightheaded, having a fast heartbeat and having a dry mouth and lips.
Feeling tired or drowsy
Fussiness
Low blood sugar
Low body temperature
Metabolic acidosis (having too much acid in body fluids)
Nausea, diarrhea and throwing up
Not eating well and having trouble gaining weight
Skin rashes or infections
Weak muscles or muscle spasms
Illness or infection, eating the wrong kinds of food or going for a long time without eating can bring about signs and symptoms of these disorders

What health problems can these disorders cause?

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

Brain damage
Coma
Eye problems and vision loss
Intellectual and developmental disabilities these are problems with how the brain works that can cause a person to have trouble or delays in physical development, learning, communicating, taking care of himself or getting along with others
Osteoporosis—causes the bones to be thin and brittle
Problems with the heart, liver, kidney or pancreas
Seizures
Stroke
If not treated, some of the disorders can lead to death

What is the treatment for organic acid disorders?

Your baby's primary doctor will work with a metabolic doctor and a dietician to provide care for your child. Prompt treatment is needed to prevent mental retardation and serious medical problems. Most children need to be on specific diet and drink a special medical formula.

The following are treatments often recommended for children with organic acid disorders:

Medications such as Vitamin B12, Biotin, Betaine, L-carnitine
Food plan such as low-protein diet, low-leucine diet, low-valine diet. Your dietician will create a food plan that contains the right amount of protein, nutrients, and energy to keep your child healthy. Your child will need to be on a special food plan throughout his or her life.
Medical formula and foods- Special medical formula contains the correct amount of protein and nutrients needed for normal growth and development. Medical foods such as special low protein flours, pastas, and rice are made especially for people with organic acid disorders.
Avoid going a long time without food: Babies and young children need to eat often to avoid a metabolic crisis. Most children should not go without food for more than 4 to 6 hours. Some children may need to eat even more often than this. It is important that babies be fed during the night. They may need to be woken up to eat if they do not wake up on their own.
Regular blood and urine tests-Your child's diet and medication may need to be adjusted based on the results of these tests.
Call your doctor at the start of any illness that can lead to a metabolic crisis. In order to prevent problems, call your doctor right away when your child has any of the following:
- Loss of appetite
- Vomiting
- Diarrhea
- Infection or illness
- Fever

Many children with organic acid disorder may need to be treated in the hospital during illness to avoid serious health problems. Ask your metabolic doctor if you should carry a special travel letter with medical instructions for your child's care.

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