Ordering Recommendation

Molecular (DNA) test to identify the causative mutations for galactosemia when GALT enzyme activity is consistent with galactosemia and the 9 mutation panel does not identify two causative mutations. To diagnose or rule out galactosemia, refer to Galactosemia (GALT) Enzyme Activity and 9 Mutations (0051175).

Mnemonic
GALT FGS
Methodology

Sequencing

Performed

Sun- Sat

Reported

14-21 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By Report

Interpretive Data

Background Information for Galactosemia (GALT), Sequencing:
Characteristics:
Vomiting, diarrhea, feeding problems, failure to thrive, hepatocellular damage, bleeding, sepsis, mental retardation, and neonatal death. If treated early, most symptoms resolve, although speech, motor problems, developmental delay and premature ovarian failure may persist.
Incidence:
Approximately 1 in 30,000.
Inheritance:
Autosomal recessive
Penetrance:
100 percent for severe mutations.
Cause:
Pathogenic galactose-1-phosphate uridyl transferase (GALT) gene mutations.
Clinical sensitivity:
98 percent.
Methodology:
  Bidirectional sequencing of the entire GALT coding region, intron/exon boundaries and partial 5'UTR.
Analytic Sensitivity & Specificity:
99 percent.
Limitations:
 Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. Mutations in genes other than GALT are not evaluated.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81406

Components
Component Test Code* Component Chart Name LOINC
2006698 Galactosemia (GALT) Sequencing Specimen
2006699 Galactosemia (GALT) Sequencing Interp
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Galactosemia Carrier Testing
  • Galactosemia Confirmation Test
  • Galactosemia genotyping
  • GALT DNA sequencing
Galactosemia (GALT), Sequencing