Alberta Precision Laboratories

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Organization:

Alberta Precision Laboratories

Message Alert:

PLEASE NOTE: This Test Directory is in an interim state and due to changes pertaining to the DynaLIFE transition, performing site for routing has not been updated. Please refer to Laboratory Information System for appropriate routing.

Test Name/Synonym:

3-Methylglutaconic & 3-Methylglutaric Acids, Blood (Synonyms: MGA, 3MGC, 3MGA, MGCA)

Clinical Indications:

Primary 3MGC Disorders Detectable by elevated 3-methylglutaconic and 3-methylglutaric acids:

3-methylglutaconyl-CoA hydratase deficiency (3MGC type I; AUH)
3-hydroxy-3-methylglutaryl-CoA lyase deficiency

Secondary 3MGC Disorders Detectable by elevated 3-methylglutaconic and 3-methylglutaric acids:

Barth syndrome (3MGC type II; TAZ)
Costeff Optic Atrophy syndrome (3MGC type III; OPA3)
MEGDEL syndrome (3MGC type IV; SERAC1)
Dilated Cardiomyopathy with Ataxia syndrome (3MGC type V; DNAJC19)
TMEM70 defect (TMEM70)

Other known causes of elevated 3-methylglutaconic and 3-methylglutaric acids

CLPB (caseinolytic peptidase B) deficiency
Carbamoyl phosphate synthetase I deficiency and other urea cycle disorders
Some mitochondrial diseases
Some neuromuscular diseases
Some glycogen storage disorders
Primary carnitine deficiency
Other metabolic disorders (due to secondary mitochondrial dysfunction)

Test Includes:

3-methylglutaconic acid, 3-methylglutaric acid

Ordering Alert:

This test is considered specialty testing; this test will be cancelled if sufficient clinical justification is not provided.

Collection Alert:

Collect following a minimum four-hour fast or just before next feeding for newborns.

LABID (Connect Care):

LAB4000

Test Code:

SOUTH ZONE (LETHBRIDGE)	MISC
SOUTH ZONE (MEDICINE HAT)	3METHYLUR, 3MGA

Specimen Type:

Blood

Primary Container:

Green top – Sodium heparin (no gel)

Alternate Containers:

Green top – Lithium heparin (no gel)
Red top – Non-additive (no gel)

Minimum Collection Volume:

1.6 mL plasma or serum

Specimen Collection Requirements:

Collect one sodium heparin (or alternate) tube.
Indicate length of fast, or time of last feeding on the requisition (with collection time).

Test Resources:

Submit request using the applicable requisition or Connect Care online order entry:

Biochemical Genetics Laboratory Requisition

Please ensure all required information, including patient's clinical history/indication, is provided on the requisition.

Stability and Storage:

Frozen - Plasma or Serum aliquot

Processing:

For ALL collection locations except for Alberta Children’s Hospital (ACH):
1. Centrifuge; If red top tube is collected, allow to fully clot prior to centrifugation.
2. Transfer plasma or serum to aliquot tube.
3. Write "NaHep", "LiHep" or "Red Top" on the aliquot tube label.
4. Freeze aliquot tube.

If collected at ACH outpatient Lab:

The primary tube can be put on ice (ensure not to freeze sample) or refrigerated for routine pick-ups between 08:30 to 14:30, Monday through Friday (excluding holidays).
If specimen is collected after 14:30, process sample as described above.

Transportation:

Transport frozen specimens on dry ice.
Samples must not thaw during transport.

Method:

Gas chromatography-mass spectrometry (GC-MS)

Method and Interpretation of Results:

3-Methylglutaconic and 3-methylglutaric acids are detected following derivatization (i.e., silylation) using a gas chromatography-mass spectrometry (GC-MS) stable isotope dilution (SID) method with a deuterium-labeled internal standard.

Urine 3-methylglutaconic and 3-methylglutaric acids can help to inform whether elevated plasma levels are due to a true 3-methylglutaconic aciduria or renal insufficiency, both of which can lead to a mild to moderate elevations of plasma 3-methylglutaconic and 3-methylglutaric acids.

This test will be reflexively performed when elevated 3-methylglutaconic and/or 3-methylglutaric acids are found by Organic Acids, Semi-Quantitative.

Routine Turn Around Time:

30 days

Testing Schedule:

Monthly

Reference Interval:

3-methylglutaconic acid	103 to 384	nmol/L
3-methylglutaric acid	15 to 87	nmol/L

Testing Area:

Biochemical Genetics

Performing Site:

Alberta Children's Hospital

Additional Test Information:

For priority turn-around contact Biochemical Genetics South Laboratory.

Contact Comments:

Biochemical Genetics 403-955-7379

Last Updated On:

Monday, July 24, 2023

Date of Last Review:

Aug 1 2022 12:00AM