Glutaric Acidemia Type 1
C5-DC (Glutarylcarnitine) Analysis
C5-DC (Glutarylcarnitine) Analysis
This test measures urine glutarylcarnitine (C5-DC) to detect glutaric acidemia, particularly type I (GA1). Although many patients with GA1 are identified through newborn screening, individuals who are considered low excretors may not be identified by this type of screening or by follow-up diagnostic testing. A low excretor will have normal or only mildly elevated biochemical analytes in the plasma, but will often have more distinctive elevations of C5-DC in the urine. Patients with glutaric acidemia type II will also typically show elevated glutarylcarnitine in urine.
Clinical Information
Glutaric acidemia type 1 (GA1) is an inborn error of lysine, hydroxylysine and tryptophan metabolism caused by the deficiency of glutaryl-CoA dehydrogenase (GCDH). GA1 is a neurodegenerative disorder with loss of neurons in the basal ganglia. Clinical features vary, but often include macrocephaly, gait abnormalities, hypotonia, spasms, rigidity and seizures. Retinal or subdural hemorrhages can also occur. Other than possible macrocephaly, patients appear normal at birth. Clinical features are typically preceded by an acute encephalopathic illness with fever before five years of age.
Technical Information
This test measures urine glutarylcarnitine using tandem mass spectrometry (MS/MS).
Specimen Requirements
Urine is the sample type for this test, and requires a minimum of 2 mL random catch urine.
Transport Instructions
The urine specimen should be frozen after collection and shipped frozen, preferably on dry ice.
Connect With Our Experts
Call 1-800-473-9411 to speak with our team of laboratory genetic counselors for questions or additional information.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC