Glutaric acidemia type I

Is genetic testing available for glutaric acidemia type I?

The Genetic Testing Registry (GTR) provides information about the labs that offer genetic testing for this condition. The intended audience for the GTR is health care providers and researchers. Therefore, patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Last updated on 05-01-20

Are all individuals with glutaric acidemia type I diagnosed as infants?

Glutaric acidemia type 1 is part of the newborn screening panel in most countries, so that treatment can be started before symptoms begin. However, even though the sensitivity of the test for GA1 is greater than 95% for most laboratories, some babies with GA1 will be missed. New methods continue to be developed to increase the sensitivity of newborn screening, but have not reached the ability to diagnose every infant born.

If the child is missed by newborn screening, they may not be diagnosed until symptoms begin after a metabolic crisis, usually in a child under 6 years old. Late onset GA1, if missed in newborn screening, will probably not be diagnosed until symptoms begin in adolescence or as an adult.

Last updated on 05-01-20

How is glutaric acidemia type I inherited?

Glutaric acidemia type I (GA1) can be passed down in families. This is because GA1 is caused by changes or mutations in the GCDH gene. Like most genes, the GCDH gene comes in a pair (two copies). One copy comes from the mother and one copy from the father. In order to have GA1, both copies of the GCDH gene must have a mutation. This means that GA1 is an autosomal recessive disorder. A person with a mutation in only one copy of the GCDH gene is called a carrier. Carriers of an autosomal recessive disease like GA1 usually have no signs or symptoms.

When 2 carriers of GA1 have children, each child has a:

  • 25% chance of having GA1
  • 50% chance to be a carrier of GA1 like each parent
  • 25% chance of not having GA1 and not being a carrier of GA1 (in other words, having two normal copies of the gene)

If a person with GA1 and a carrier of GA1 have children, each child has a:

  • 50% chance of having GA1
  • 50% chance of being a carrier

If a person with GA1 and a person who has two normal copies of the GCDH gene have children, each child will be a carrier of GA1.

Last updated on 05-01-20

If my husband is a carrier but I am not, are our children at risk to develop glutaric acidemia type I?

If your husband is a carrier but you are not, it is very unlikely that your children will have glutaric acidemia type I (GA1). As mentioned above, both copies of the GCDH gene must have a change or mutation in order to have GA1. And remember, one copy of the gene comes from the father and one copy from the mother.

Therefore if a carrier of GA1 (one normal copy of the GCDH gene and one copy of the gene) and a person who does not have GA1 and is not a carrier (so has two normal copies of the GCDH gene) has a child, each child has a:

  • 50% chance of being a carrier of GA1
  • 50% chance of not having GA1 and not being a carrier of GA1 (has two normal copies of the GCDH gene)

In theory, there is a very small risk that one of several complex, but rare genetic accidents can happen so that a child could end up with a mutation in both copies of the GCDH gene. This is why a genetic counselor will not say there is no risk of having a child with GA1. However, we were not able to find any reported cases in the published medical journal articles of this happening.

Last updated on 05-01-20

What is the long-term outlook for people with glutaric acidemia type I?

Glutaric acidemia type 1 (GA1) is a treatable disorder. If treatment begins in the newborn period before symptoms begin, and the treatment is followed properly, children with GA1 usually grow and develop normally. However, since newborn screening for GA1 (allowing treatment to begin before symptoms) only began in the 1990s, it is not yet known if GA1 may cause complications later in life.

If not promptly and properly treated, GA1 usually causes serious, irreversible, neurologic damage. The damage mainly affects control of voluntary muscle movement. The overall impact of GA1 on a person's life will depend on the amount of damage to the brain, but can be severe. In general, a person with GA1 who has an acute brain damaging episode before the age of 6 years old is at increased risk for medical problems throughout their life, and their life expectancy is shortened.

Last updated on 05-01-20

Newborn Screening

Glutaric acidemia type 1

The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.

Last updated on 04-27-20

Name: Metabolic Support UK 5 Hilliards Court Sandpiper Way
Chester Business Park
Chester, CH4 9QP, United Kingdom
Phone: 0845 241 2173 Toll Free: 0800 652 3181 Email: https://www.metabolicsupportuk.org/contact-us Url: https://www.metabolicsupportuk.org
Name: Organic Acidemia Association 9040 Duluth Street
Golden Valley, MN, 55427, United States
Phone: 763-559-1797 Fax : 866-539-4060 Email: mkstagni@gmail.com Url: http://www.oaanews.org/
Name: Genetic Metabolic Dietitians International P.O. Box 1462
Hillsborough, NC, 27278, United States
Email: info@gdmi.org Url: http://www.gmdi.org/
Name: Alex The Leukodystrophy Charity Alex TLC 45 Peckham High Street
London, SE15 5EB, United Kingdom
Phone: 020 7701 4388 Email: info@alextlc.org Url: https://www.alextlc.org
Seashore MR. The organic acidemias: An overview Gene Reviews. 2001; Reference Link

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