Test Code 2HGA 2-Hydroxyglutaric Acid Chiral Analysis, Quantitative, Random, Urine
Necessary Information
1. Age and sex of patient are required.
2. Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Specimen Required
Supplies: Urine Tube, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 10 mL
Pediatric: If the collection volume appears insufficient, submit as much specimen as possible in a single container; the laboratory will determine if volume is sufficient for test.
Collection Instructions:
1. Collect a random urine specimen (first morning void preferred)
2. No preservative
Useful For
Determining type of 2-hydroxyglutaric aciduria by chiral analysis of urine
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Reporting Name
D-,L- 2-Hydroxyglutaric Acid, QN, USpecimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Frozen (preferred) | 416 days | |
Ambient | 14 days | ||
Refrigerated | 14 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
2-Hydroxyglutaric aciduria disorders are a group of cerebral organic acidurias that present biochemically with an elevation of 2-hydroxyglutaric acid (2-HGA) in the urine. There are 2 enantiomers of 2-HGA, the D-form and the L-form. Depending on the genetic defect, individuals may have an elevation of one or both forms of 2-HGA. Routine organic acid analysis (OAU / Organic Acids Screen, Random, Urine), while able to detect 2-HGA, is unable to distinguish between the 2 enantiomers; however, they can be separated with this more specialized biochemical test.
L-2-hydroxyglutaric aciduria (L-2-HGA) is caused by defects in L2HGDH and is characterized by progressive cerebellar ataxia and intellectual disability, seizures, and macrocephaly beginning in infancy or early childhood. Symptoms worsen over time, leading to severe disability by early adulthood. Magnetic resonance imaging (MRI) findings include subcortical leukoencephalopathy, generalized cerebellar and cerebral atrophy, and atrophy of the corpus callosum.
D-2-hydroxylglutaric aciduria (D-2-HGA) is characterized by elevated levels of D-2-hydroxyglutaric acid (D-2-HG) and typically manifests with developmental delay, seizures, and hypotonia, though can vary widely from asymptomatic to severe. There are 2 types of D-2-HGA depending on the genetic cause. D-2-HGA can either be autosomal recessive, resulting from variants in D2HGDH causing reduced enzymatic activity (type I), or autosomal dominant, with gain-of-function variants in IDH2 causing overproduction of D-2-HG (type II).
Combined D,L-2-hydroxylglutaric aciduria (D,L-2-HGA) is the most severe of the 3 types and is caused by defects in SLC25A1, which encodes the mitochondrial citrate carrier. It is characterized by neonatal-onset encephalopathy with severe muscular weakness, intractable seizures, respiratory distress, and lack of psychomotor development resulting in early death.
Molecular genetic testing is available (2OHGP / 2-Hydroxyglutaric Aciduria Gene Panel, Varies), which includes analysis of D2HGDH, L2HGDH, IDH2, and SLC25A1 and can be used to confirm abnormal urine results.
Reference Values
Age |
D-2-hydroxyglutaric acid (mmol/mol creatinine) |
L-2-hydroxyglutaric acid |
0-11 months |
≤14.11 |
≤17.38 |
12-23 months |
≤13.76 |
≤17.03 |
24-35 months |
≤13.38 |
≤16.63 |
3 years |
≤12.96 |
≤16.18 |
4 years |
≤12.20 |
≤15.35 |
5 years |
≤11.40 |
≤14.44 |
6 years |
≤10.56 |
≤13.46 |
7 years |
≤9.71 |
≤12.43 |
8 years |
≤8.93 |
≤11.44 |
9 years |
≤8.21 |
≤10.50 |
10 years |
≤7.56 |
≤9.66 |
11 years |
≤6.99 |
≤8.94 |
12 years |
≤6.47 |
≤8.33 |
13 years |
≤6.01 |
≤7.83 |
14 years |
≤5.60 |
≤7.44 |
15 years |
≤5.23 |
≤7.14 |
16 years |
≤4.91 |
≤6.93 |
17 years |
≤4.63 |
≤6.78 |
18 years |
≤4.40 |
≤6.69 |
19 years |
≤4.21 |
≤6.63 |
20 years |
≤4.07 |
≤6.60 |
21 years |
≤3.96 |
≤6.59 |
22 years |
≤3.88 |
≤6.58 |
23 years |
≤3.81 |
≤6.56 |
24 years |
≤3.76 |
≤6.54 |
25 years |
≤3.71 |
≤6.50 |
26 years |
≤3.67 |
≤6.44 |
27 years |
≤3.63 |
≤6.37 |
28 years |
≤3.59 |
≤6.27 |
29 years |
≤3.56 |
≤6.15 |
30 years |
≤3.54 |
≤6.02 |
31 years |
≤3.52 |
≤5.87 |
32 years |
≤3.50 |
≤5.72 |
33 years |
≤3.49 |
≤5.57 |
34 years |
≤3.48 |
≤5.41 |
35 years |
≤3.46 |
≤5.26 |
36 years |
≤3.45 |
≤5.13 |
37 years |
≤3.43 |
≤5.00 |
38 years |
≤3.42 |
≤4.88 |
39 years |
≤3.40 |
≤4.78 |
40 years |
≤3.39 |
≤4.70 |
41 years |
≤3.37 |
≤4.62 |
42 years |
≤3.35 |
≤4.55 |
43 years |
≤3.33 |
≤4.50 |
44 years |
≤3.30 |
≤4.44 |
45 years |
≤3.28 |
≤4.40 |
46 years |
≤3.24 |
≤4.35 |
47 years |
≤3.21 |
≤4.31 |
48 years |
≤3.17 |
≤4.27 |
49 years |
≤3.13 |
≤4.23 |
50 years |
≤3.10 |
≤4.19 |
51 years |
≤3.07 |
≤4.16 |
52 years |
≤3.04 |
≤4.12 |
53 years |
≤3.01 |
≤4.10 |
54 years |
≤2.99 |
≤4.07 |
55 years |
≤2.97 |
≤4.04 |
56 years |
≤2.95 |
≤4.01 |
57 years |
≤2.93 |
≤3.98 |
58 years |
≤2.91 |
≤3.94 |
59 years |
≤2.89 |
≤3.91 |
60 years |
≤2.87 |
≤3.87 |
61 years |
≤2.85 |
≤3.84 |
62 years |
≤2.83 |
≤3.80 |
63 years |
≤2.79 |
≤3.78 |
64 years |
≤2.76 |
≤3.75 |
65 years |
≤2.71 |
≤3.73 |
66 years |
≤2.67 |
≤3.72 |
67 years |
≤2.61 |
≤3.71 |
68 years |
≤2.56 |
≤3.69 |
69 years |
≤2.50 |
≤3.68 |
70 years |
≤2.44 |
≤3.66 |
71 years |
≤2.38 |
≤3.64 |
72 years |
≤2.32 |
≤3.61 |
73 years |
≤2.26 |
≤3.56 |
74 years |
≤2.21 |
≤3.50 |
75 years |
≤2.16 |
≤3.43 |
76 years |
≤2.10 |
≤3.35 |
77 years |
≤2.05 |
≤3.26 |
78 years |
≤2.00 |
≤3.17 |
79 years |
≤1.94 |
≤3.08 |
80 years |
≤1.89 |
≤2.99 |
81 years |
≤1.84 |
≤2.91 |
82 years |
≤1.80 |
≤2.84 |
83 years |
≤1.75 |
≤2.78 |
84 years |
≤1.71 |
≤2.73 |
85 years |
≤1.68 |
≤2.69 |
86 years |
≤1.65 |
≤2.67 |
87 years |
≤1.64 |
≤2.65 |
88 years |
≤1.63 |
≤2.64 |
≥89 years |
≤1.62 |
≤2.64 |
Day(s) Performed
Thursday
Report Available
3 to 9 daysPerforming Laboratory
Mayo Clinic Laboratories in RochesterTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83921 x 2
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.