Conditions Glutaric Acidemia, Type I

Glutaric acidemia, type I is a different condition from glutaric acidemia type II. You can learn about the detection, causes, and treatment on the condition page for glutaric acidemia, type II.

Glutaric acidemia, type I (GA-1) is an inherited condition in which the body is unable to break down certain proteins properly. It is considered an organic acid condition because GA-1 can lead to a harmful amount of organic acids and toxins in the body. If the condition is left untreated, it can cause brain defects or even death. However, if the condition is identified early in life and proper treatment is begun, children with GA-1 can often lead healthy lives.

Condition Type

Organic Acid Conditions

Frequency

How common is glutaric acidemia, type I?

Glutaric acidemia, type I affects about one 1 of every 40,000 babies born in the United States. Glutaric acidemia, type I is more common in the Amish population of the United States, in the Ojibway Indian population of Canada, and among people of Swedish ancestry.

Also known as

  • GA-1
  • Glutaryl-CoA dehydrogenase deficiency
  • Dicarboxylic aminoaciduria
  • Glutarate-aspartate transport defect
  • Glutaric aciduria type I

Follow-Up Testing

Your baby’s doctor may ask you if your baby is showing any of the signs of glutaric acidemia, type I (GA-1) (see Early Signs below). If your baby has certain signs, your baby’s doctor may suggest starting immediate treatment.

If your baby’s newborn screening result for GA-1 was out of the normal range, your baby’s doctor or the state screening program will contact you to arrange for your baby to have additional testing. It is important to remember that an out-of-range screening result does not necessarily mean that your child has the condition. An out-of-range result may occur because the initial blood sample was too small or the test was performed too early. However, a few babies do have the condition, so it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated GA-1 can occur within days after birth, follow-up testing must be completed as soon as possible to determine whether or not your baby has the condition.

Follow-up testing will involve checking your baby’s urine and blood samples for harmful levels of acids and toxins. Certain acids and toxins build up in the body when a child has an organic acid condition, so studying the amount of these substances in your baby’s body can help doctors determine if your baby has a condition. A high level of 3-hydroxyglutaric acid in the urine might be a sign of GA-1. In some cases, follow-up testing may also include testing a very small sample of skin.

About Glutaric Acidemia, Type I

Early Signs

At birth, you may not notice anything different about your baby, although some babies with glutaric acidemia, type 1 (GA-1) do have a larger than average head. 

Babies who are identified through newborn screening can begin treatment for the condition before signs of GA-1 start. 

A baby with GA-1 who has not been treated will start to show signs between 4 months and 2 years of age. These signs include:

  • Poor appetite
  • Sleeping longer or more often
  • Tiredness
  • Irritability
  • Twitches
  • Vomiting
  • Weak muscle tone (called hypotonia)
  • Fever
  • Delayed growth
  • Rigid muscles (known as spasticity)
  • Developmental delays
  • Excessive sweating

Many of these signs may occur when your baby eats foods that his or her body cannot break down. They can be triggered by long periods of time without eating, illnesses, and infections.

The severity of GA-1 varies highly for each individual. You may see many of these signs or none at all.

If your baby shows any of these signs, be sure to contact your baby’s doctor immediately.

Treatment
Dietary Treatments

It is important to start treatment as soon as glutaric acidemia, type 1 (GA-1) is diagnosed to avoid many of the signs of GA-1 mentioned in the Early Signs section. Feeding your baby often and treating illnesses and infections can also help prevent these signs.

Your baby will also need a carefully planned diet in order to avoid the proteins your baby’s body is unable to break down but to still have enough nutrients for healthy growth. A dietician or nutritionist can help you manage your child’s diet.

Supplements and Medication

Your baby’s doctor might prescribe supplements like riboflavin. Riboflavin is a natural substance that helps the body break down proteins. It can also help reduce acid levels in your baby’s body. There is always some acid in the body, but very high levels can be toxic. GA-1 causes acid levels to increase.

L-carnitine is another natural supplement that your baby’s doctor might recommend. L-carnitine helps your baby’s body get rid of harmful wastes. Your baby’s doctor will need to write prescriptions for these supplements.

Expected Outcomes

If glutaric acidemia, type 1 (GA-1) is treated early and throughout life, your baby can have healthy growth and development.

Some children have experienced signs of GA-1 even with treatment, but these tend to decrease with age. Many of these signs are very infrequent after age 6. These children can also develop intellectual disabilities.

It is important to screen for and treat GA-1 early. If GA-1 is untreated, it can lead to seizures, coma, or permanent brain damage.

Causes

When we eat food, enzymes help break it down. Some enzymes help break down proteins into their building blocks, called amino acids. Other enzymes break down the amino acids. In glutaric acidemia, type 1 (GA-1) the enzyme “glutaryl-CoA dehydrogenase” is not working correctly.

This enzyme’s job is to break down the amino acids lysine, hydroxylysine, and tryptophan.

GA-1 occurs when your baby’s body either doesn’t make enough or makes malfunctioning glutaryl-CoA dehydrogenase enzymes. When your baby’s body cannot break down these substances, harmful substances build up in the body.

These harmful substances tend to accumulate in the basal ganglia, which are areas of the brain that control movement. This causes the neurological symptoms of GA-1.

GA-1 is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for GA-1, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition. While having a child with GA-1 is rare, when both parents are carriers, they can have more than one child with the condition. Learn more about autosomal recessive inheritance.

Support for Glutaric Acidemia, Type I

Support Services

Support groups can help connect families who have a child or other family member affected with glutaric acidemia with a supportive community of people who have experience and expertise in living with the condition. These organizations offer resources for families, affected individuals, health care providers, and advocates.

Accessing Care

Work with your baby’s doctor to determine the next steps for your baby’s care.  Your baby’s doctor may help you coordinate care with a physician who specializes in metabolism, a dietician who can help plan your child’s specialized diet, or other medical resources in your community. Some children with glutaric acidemia, type I (GA-1) have developmental delays. If you think that your baby is not meeting his or her developmental milestones, ask your baby’s about the next steps in accessing a developmental evaluation and care.

Because GA-1 is a genetic condition, you may want to talk with a genetics specialist. A genetic counselor or geneticist can help you understand the causes of the condition, discuss genetic testing for GA-1, and understand what this diagnosis means for other family members and future pregnancies. Speak with your baby’s doctor about getting a referral. The Clinic Services Search Engine offered by the National Coordinating Center for the Regional Genetic and Newborn Screening Service Collaboratives and the Find a Genetic Counselor tool on the National Society of Genetic Counselors (NSGC) website are two good resources for you or your baby's health care provider to use to identify local specialists.

Families' Experiences

Sarah Grace is a young girl who was diagnosed with glutaric acidemia, type I (GA-1) through newborn screening. Sarah has faced many health challenges, but her family is optimistic about the future. You can read her story on a website dedicated to her.

Julia is a young girl with GA-1. Learn about her struggles and successes in this inspiring video posted on YouTube.

The Organic Acidemia Association (OAA) publishes the stories of people who are affected by glutaric acidemia. You can read their stories by clicking on the family photos at the bottom of this page of the OAA website.

The International Organization of Glutaric Acidemia (IOGA) also collects the stories of families with GA-1. You can read these stories on the IOGA website.

References & Sources

Visit Genetics Home Reference from the National Library of Medicine for more condition information
http://ghr.nlm.nih.gov/condition/glutaric-acidemia-type-i
Visit the Screening, Technology And Research in Genetics (STAR-G) Project for more information on GA-1
http://www.newbornscreening.info/Parents/organicaciddisorders/GA1.html
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