ARUP's Laboratory Test Directory
| 0051175: Galactosemia, (GALT) Enzyme Activity & 9 Mutations |
![[ image for: Patient History For Galactosemia]](icon_19.jpg){kind=icon} | Patient History For Galactosemia |
| Test Mnemonic: GALTPAN | |
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Methodology: Enzymatic/Polymerase Chain Reaction/Single Nucleotide Extensions
Performed: Tue, Thu Reported: 7-10 days |
| Specimen Required: | |
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Collect: Two 5 mL lavender (EDTA), pink (K2EDTA), or green (sodium heparin).
Transport: Two 5 mL whole blood at 2-8°C. (Min: 3 mL) Pediatric Collection/Transport: 3 mL whole blood at 2-8°C. Remarks: Do not freeze. Unacceptable Conditions: Frozen or ambient specimens. Stability: Ambient: Unacceptable; Refrigerated: 5 days; Frozen: Unacceptable |
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| Reference Interval: |
| By report |
| Interpretive Data: | |
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Background Information: Characteristics: Affected infants present at 3-14 days old with poor feeding, vomiting, diarrhea, jaundice, lethargy progressing to coma, and abdominal distension with hepatomegaly usually followed by progressive liver failure. Patients with galactosemia are also at increased risk for E. coli or other Gramnegative neonatal sepsis. Diagnosis is made by measuring GALT enzyme activity in red blood cells. Incidence: Approximately 1:120 in Caucasians; less common in other ethnic groups. Inheritance: Autosomal recessive Penetrance: 100% for severe GALT mutations Cause: Mutations in the GALT gene. Mutations Detected: Seven GALT gene mutations (Q188R, S135L, K285N, T138M, L195P, Y209C, and IVS2-2 A>G) and two variants (N314D and L218L). Clinical Sensitivity DNA: Approaches 80% in Caucasians but reduced in other ethnic groups. Methodology DNA: Polymerase chain reaction followed by single nucleotide extension (SNE) and capillary electrophoresis. Analytical Sensitivity DNA: 99% for mutations listed. Limitations DNA: Other mutations will not be detected. Methodology Enzymatic: Spectrophotometric quantitation of enzyme activity in red blood cells. This test is performed pursuant to an agreement with Roche Molecular Systems, Inc. Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com. Please refer to Statement C in the Compliance Statements section in the front of the Laboratory Test Directory. |
| CPT Code(s): | |
| 82775 Enzymatic; PCR: 83890 Isolation; 83898 Amplification; 83914 x9 Mutation identification; 83909 Capillary Electrophoresis; 83912 Interpretation and report - Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders. |