Galactosemia, (GALT) 9 Mutations
Ordering Recommendation

Molecular (DNA) test to identify the causative mutations when GALT enzyme activity is known. To diagnose or rule out galactosemia, refer to Galactosemia (GALT) Enzyme Activity and 9 Mutations (0051175).

Polymerase Chain Reaction/Single Nucleotide Extensions
Mon, Wed, Fri
7-10 days
New York DOH Approval Status
This test is New York DOH approved.
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or green (sodium heparin). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
By report
Interpretive Data
Interpretive Data:
Background Information for Galactosemia (GALT) 9 Mutations:
: 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 gram-negative neonatal sepsis. Diagnosis is made by measuring GALT enzyme activity in red blood cells.
Approximately 1 in 30,000 to 60,000 of classic galactosemia in Caucasian, varies in other populations.
: Autosomal recessive.
: 100 percent for severe GALT mutations.
Mutations in the GALT gene.
Mutations Tested:
Seven GALT gene mutations (Q188R, S135L, K285N, T138M, L195P, Y209C, and IVS2-2 A>G) and two variants (N314D and L218L).
Clinical Sensitivity
: Approaches 80 percent in Caucasians but reduced in other ethnic groups.
: Polymerase chain reaction followed by single nucleotide extension (SNE) and capillary electrophoresis.
Analytical Sensitivity:
99 percent for mutations listed.
GALT gene mutations, other than the 9 targeted, will not be detected. Diagnostic errors can occur due to rare sequence variations.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online at

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

This test is offered to individuals with known familial mutation(s).
Component Test Code*Component Chart NameLOINC
0051177Galactosemia - Ethnicity42784-9
0051178Galactosemia - Symptoms
0051180Galactosemia - Family History8670-2
0051182Galactosemia (GALT) Allele 142940-7
0051183Galactosemia (GALT) Allele 242941-5
0051184Galactosemia (GALT) DNA Panel Interp50398-7
2001351Galactosemia (GALT) DNA Panel Specimen
* 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.
  • Galactosemia Carrier Testing
  • Galactosemia Confirmation Test
  • Galactosemia genotyping