Organic acid metabolism disorders
Your baby gets newborn screening tests before he leaves the hospital after birth. These tests look for rare but serious and mostly treatable health disorders that affect how the body works.
Your baby’s newborn screening may include testing for certain organic acid metabolism disorders. These are rare health conditions that affect a body’s metabolism. Metabolism is the way your body changes food into the energy it needs to breathe, digest food and grow.
Organic acid metabolism disorders are inherited. This means they’re 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. In the United States, all babies have newborn screening tests to see if they may have certain inherited conditions when they’re born.
With early diagnosis and treatment, most babies with these disorders can lead healthy lives. Without treatment, the disorders can lead to serious health problems and even death. This is why newborn screening right after birth is so important. People with these condition usually need treatment for their whole life.
For more information on these disorders, go to genetests.org.
How do these kinds of disorders affect a person’s body?
Some of these disorders affect the way the body uses amino acids. Amino acids help build protein in your body. For people with disorders that affect amino acids, eating foods that are high in protein can cause serious health problems and sometimes death.
Some of the disorders affect how the body makes or uses ketones. Ketones are chemicals that the body makes when it breaks down fat for energy. Your body uses ketones for energy when you don’t eat for a long time. Other disorders affect how the body uses vitamins, protein and carbohydrates (sugar) in food.
People with these kinds of disorders may need to limit or avoid certain foods because their bodies can’t process them properly.
What organic acid metabolism disorders are tested for in newborn screening?
The March of Dimes recommends that all babies be screened for these organic acid metabolism disorders:
- 3-methylcrotonyl-CoA carboxylase deficiency (also called 3MCC). If your baby has 3MCC, his 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 1 in 75,000 babies is born with 3MCC.
- Beta-ketothiolase deficiency (also called BKT). If your baby has this disorder, her body can’t use the amino acid isoleucine and can’t use ketones. Fewer than 1 in 100,000 babies is born each year in the United States with BKT.
- Glutaric acidemia type 1 (also called GA1). If your baby has this condition, her body can’t 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 1 in 75,000 babies is born with GA1.
- Hydroxymethylglutaric aciduria (also called HMG). If your baby has HMG, his body 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, fewer than 1 in 100,000 babies is born with HMG.
- Isovaleric acidemia (also called IVA). Like 3MCC, in this condition your baby’s body has trouble breaking down leucine. Each year in the United States, fewer 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. Fewer than 1 in 100,000 babies is born each year in the United States with this disorder.
- Methylmalonic acidemia, mutase deficiency form (also called MUT). This disorder is similar to Cbl A,B. More than 1 in 750,000 babies is born each year in the United States with MUT.
- Multiple carboxylase deficiency (also called MCD). In MCD, your baby’s body can’t use a vitamin called biotin. Biotin is a B vitamin that’s in foods like eggs and milk. The body uses biotin when it makes and breaks down proteins, fats and carbohydrates. Fewer than 1 in 100,000 babies is born with MCD each year in the United States.
- Propionic acidemia (also called PROP). Like in CblA,B and MUT, your baby’s body can’t 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 1 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. And signs and symptoms may appear and then go away over time. Each disorder has different signs and symptoms, but they often include:
- Dehydration. This means you don’t have enough water in your body. Signs of dehydration include feeling dizzy or lightheaded, having a fast heartbeat and having a dry mouth and lips.
- Feeling tired or drowsy
- 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
- 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. This is a disease that causes the bones to be thin and brittle.
- Problems with the heart, liver, kidney or pancreas
- Stroke. This is when normal blood flow to the brain is stopped.
If not treated, some of the disorders can lead to death.
See also: Newborn screening
Last reviewed: January, 2014