Clinical use
This test is valuable for detecting most of the fatty acid oxidation disorders including
- Very Long Chain Acyl-CoA Dehydrogenase Deficiency
- Carnitine palmitoyltransferase II deficiency (CPT II deficiency)
- Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency (LCHAD deficiency) or tri-functional protein deficiency
- Medium-chain acyl-coenzyme A dehydrogenase deficiency (MCAD deficiency)
- Multiple acyl-CoA dehydrogenase deficiency (MADD deficiency)
- Short-chain acyl-coenzyme A deficiency (SCAD deficiency).
The test can also detect many of the more common organic acid disorders such as isovaleric acidemia, propionic acidemia, methymalonic acidemia, thiolase deficiency and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency.
Background
Acyl CoA dehydrogenase enzymes are located within mitochondria and play a vital role in the b-oxidation pathway of energy production. LCAD metabolises acyl-CoA with chain lengths C12 – C18; MCAD metabolises acyl-CoA with chain lengths C8 – C12.Deficiencies in these enzymes lead to an inability to mobilise fat for energy production putting the individual at risk for hypoketotic hypoglycaemia when stressed – associated symptoms may be metabolic acidosis, encephalopathy and hepatomegaly.
Analysis of the (chain length) acyl-carnitine profile in blood and urine taken when the patient is symptomatic should enable a diagnosis of acyl-CoA deficiency to be made.
Deficiency of this class of enzyme has been implicated in sudden unexpected death in infancy (SUDI).
Patients with peroxisomal biogenesis disorders such as Zellweger’s syndrome or with acidaemias may also show abnormal profiles of circulating acylcarnitines.
Patient preparation
None required
Specimen requirements
- Urine: Random sample collected in a plain 25ml container
- Blood: Blood spot (Guthrie card)
Turnaround time
6 weeks
Analysing Laboratory
Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP