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Unit Code 88831:
C5-DC Acylcarnitine, Quantitative, Urine

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Useful For

Evaluation of patients with an abnormal newborn screen showing

elevations of C5-DC

 

Diagnosis of GA-1 deficiency

Clinical Information

An isolated elevation of glutarylcarnitine (C5-DC) in newborn

screening blood spots is related to a diagnosis of glutaryl-CoA

dehydrogenase (GA-1) deficiency. Follow-up testing is necessary

to confirm the diagnosis. The American College of Medical Genetics

(ACMG) newborn screening work group published diagnostic

algorithms for the follow-up of infants who had a positive newborn

screening result--see

http://www.acmg.net/resources/policies/ACT/Visio-C5-DC(4-29-06).pdf.

Urinary excretion of C5-DC is a specific biochemical marker of GA-1;

it can be particularly useful in the workup of patients without glutaric

aciduria, a finding in most, but not all, cases of GA-1 deficiency.

Reference Values

<1.54 millimoles/mole creatinine

Interpretation

Elevated excretion of C5-DC is a specific biochemical marker of

GA-1 that also appears to be elevated in the so-called

"low excretors" group (normal glutaric acid excretion).

Cautions

The results of urine acylcarnitines are not informative when

the patient is receiving L-carnitine supplements.

Clinical Reference

Tortorelli S, Hahn SH, Cowan TM, et al:  The urinary excretion of

glutarylcarnitine is an informative tool in the biochemical diagnosis

of glutaric acidemia type I. Mol Genet Metab 2005;84:137-143

Key