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.