Glutaric aciduria type I (GA-I)

Alternative name Glutaryl-CoA dehydrogenase deficiency
About the condition GA-I is an organic acid disorder. It is a hereditary disease that is caused by a missing enzyme needed to metabolise the amino acids lysine, hydroxylysine and tryptophan. There is specific damage to the basal ganglia in the brain.
Inheritance Autosomal recessive
Year screening started in WA 
2005 
Incidence in Australia Currently unknown
Enzyme defect Deficiency of the enzyme glutaryl-CoA dehydrogenase, which metabolises lysine, hydroxylysine and tryptophan.
Symptoms if untreated
  • Vomiting
  • Macrocephaly
  • Encephalopathic crises
  • Movement disorder, dystonia
  • Seizures
  • Coma and death possible
Metabolites on bloodspot screening
  • Increased glutarylcarnitine (C5DC)
  • Increased C5DC/C5OH ratio
Diagnostic tests
  • Plasma acylcarnitine profile
  • Plasma amino acids
  • Urine organic acids
  • GCDH gene analysis
Treatment
  • Lysine and tryptophan restricted diet
  • Carnitine supplementation
  • Riboflavin supplementation
  • IV glucose and supportive measures during crisis episodes
Screening issues A proportion of patients are "low excretors" and biochemical detection may not be reliable.