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Glutaric Acidemia Type I (GA I)

Last updated April 13, 2018

Approved by: Maulik P. Purohit MD, MPH

Glutaric Acidemia Type I (GA I) is a rare and inherited genetic disorder. In this disorder, there is decreased amount of enzymes that breakdown certain proteins, resulting in the abnormal protein accumulation in the cells.

What are the other Names for this Condition? (Also known as/Synonyms)

  • GA I (Glutaric Acidemia I)
  • Glutaric Aciduria I
  • Glutaryl-CoA Dehydrogenase Deficiency

What is Glutaric Acidemia Type I? (Definition/Background Information)

  • Glutaric Acidemia Type I (GA I) is a rare and inherited genetic disorder. In this disorder, there is decreased amount of enzymes that breakdown certain proteins, resulting in the abnormal protein accumulation in the cells
  • This abnormal protein accumulation causes a variety of systems and organs to function improperly. Depending upon the severity of the condition, some individuals may have mild symptoms, while others may have severe symptoms
  • The signs and symptoms of Glutaric Acidemia Type I may include excessive crying, irritability, poor feeding (all noted particularly in infants), and muscle weakness, easy bruising, and low blood sugar
  • Since Glutaric Acidemia Type I is caused by a genetic mutation, it cannot be prevented. The condition is treated using medications and through proper dietary control
  • The prognosis of Glutaric Acidemia Type I is dependent upon several factors including its severity and the presence of complications 

Who gets Glutaric Acidemia Type I? (Age and Sex Distribution)

  • Glutaric Acidemia Type I is a congenital condition that has an incidence of about 1 in 30,000-40,000
  • The condition is manifested at birth or infancy, in most cases. In some cases, the signs and symptoms may not be noticed until adolescence or early adulthood
  • Both male and female genders are prone to this disorder
  • All racial and ethnic groups may be affected, though GA I is seen in a very high prevalence rate within the Amish community, individuals of Swedish ancestry, and in a certain native Indian population found in Canada (the Ojibwas)

What are the Risk Factors for Glutaric Acidemia Type I? (Predisposing Factors)

  • A positive family history of Glutaric Acidemia Type I is the only known risk factor for the condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Glutaric Acidemia Type I? (Etiology)

  • Glutaric Acidemia Type I is a genetic disorder that is inherited in an in an autosomal recessive pattern
  • In this disorder, there are genetic mutations in the GCDH gene, which is responsible for the production of glutaryl-CoA dehydrogenase enzyme
  • Due to the mutation, the gene functions abnormally and causes the buildup of intermediate products within the body (high level of protein accumulation), resulting in the various signs and symptoms

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children, born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Glutaric Acidemia Type I?

In a majority of cases, the condition is onset during infancy; while in mild cases, it may not be apparent until the individual reaches adolescence or even adulthood. The signs and symptoms of Glutaric Acidemia Type I may include:

  • Large head
  • Muscle weaknesses
  • Poor feeding
  • Excessive crying
  • Easy bruising
  • Low blood sugar
  • Vomiting

The signs and symptoms of GA I may become worse, due to an increase in stress to the body, such as caused by an infection.

How is Glutaric Acidemia Type I Diagnosed?

Glutaric Acidemia Type I may be diagnosed using the following tools:

  • Complete physical examination with evaluation of medical history
  • This includes screening of the newborn baby having a family history the disorder, which is very important
  • Urine and blood analysis
  • Genetic tests and analysis to detect mutations
  • Prenatal exams include amniocentesis and chorionic villus sampling

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Glutaric Acidemia Type I?

Complications due to Glutaric Acidemia Type I that occur usually after brain degeneration due to toxicity may include:

  • Neurological and muscular abnormalities: Difficulty walking, moving, sitting, muscular spasms, body rigidity, decreased muscle tone and weakness, mental retardation
  • Bleeding in the eyes and brain

How is Glutaric Acidemia Type I Treated?

When Glutaric Acidemia Type I manifest immediately after birth, rapid and intensive treatment methods are required to effectively control its harmful effects. In other cases where the symptoms appear between early childhood and adolescence stage, prompt management is still required. These treatment steps may include:

  • Oral medication - to help body process reduced levels of glutaric acid, or to eliminate wastes from the body quicker (such as vitamin B2 or riboflavin, carnitine supplements)
  • If the condition is serious, known as a metabolic crisis, intravenous injections, such as carnitine, glucose, and insulin, may be provided
  • Frequent feeding is advised (4-6 hours for an infant) so as to prevent any metabolic adversities; special medical formulas for babies are also available
  • Strict dietary regimen: The prescribed diet contains low levels of amino acids such as lysine and tryptophan. The excluded food normally includes milk and milk products, eggs, chicken, meat, fish, nuts, and legumes
  • Regular blood and urine tests are required to monitor the child
  • If there are any signs of fever, vomiting, illness, sleeplessness, or appetite loss that are noticed, then prompt medical attention has to be provided
  • Occupational and physical therapy for muscular ailments and associated abnormalities

How can Glutaric Acidemia Type I be Prevented?

  • Currently, there are no specific methods or guidelines to prevent Glutaric Acidemia Type I, since it is a genetic condition
  • Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
  • If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
  • Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Glutaric Acidemia Type I
  • Regular medical screening at periodic intervals with tests, and physical examinations are mandatory

What is the Prognosis of Glutaric Acidemia Type I? (Outcomes/Resolutions)

  • Children with Glutaric Acidemia Type I require prompt, continuous, and lifelong medical support and management of the condition; a strict diet compliance has to be maintained to limit progression of the disorder
  • The recurrence of metabolic crises reduces after age 6; however, in spite of treatment in some children, long-term muscular damage and neurological complications may occur

Additional and Relevant Useful Information for Glutaric Acidemia Type I:

There are voluntary organizations and support groups that provide help and understanding to the families and parents of the Glutaric Acidemia Type I disorder affected.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 21, 2015
Last updated: April 13, 2018