Galactosemia, (GALT) 9 Mutations
0051176
 
Ordering Recommendation
Diagnostic testing for galactosemia or carrier screening for galactosemia.
Mnemonic
GALTDNA
Methodology
Polymerase Chain Reaction/Single Nucleotide Extensions
Performed
Tue, Thu
Reported
7-10 days
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), pink (K2EDTA), or green (sodium heparin).  
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
Interpretive Data:
Background Information for Galactosemia (GALT) 9 Mutations:
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 gram-negative neonatal sepsis. Diagnosis is made by measuring GALT enzyme activity in red blood cells.
Incidence:
Approximately 1 in 30,000 to 60,000 of classic galactosemia in Caucasian, varies in other populations.
Inheritance
: Autosomal recessive.
Penetrance
: 100 percent for severe GALT mutations.
Cause:
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.
Methodology
: Polymerase chain reaction followed by single nucleotide extension (SNE) and capillary electrophoresis.
Analytical Sensitivity:
99 percent for mutations listed.
Limitations:
GALT gene mutations, other than the 9 targeted, will not be detected. Diagnostic errors can occur due to rare sequence variations.

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.



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

See Compliance Statement C: www.aruplab.com/CS
Note
This test is offered to individuals with known familial mutation(s).
CPT Code(s)
81401
Components
Component Test Code*Component Chart Name
0051177Galactosemia - Ethnicity
0051178Galactosemia - Symptoms
0051180Galactosemia - Family History
0051182Galactosemia (GALT) Allele 1
0051183Galactosemia (GALT) Allele 2
0051184Galactosemia (GALT) DNA Panel Interp
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, contact interface support at interface.support@aruplab.com.
Cross References