Galactosemia (GALT) 9 Mutations, Fetal
0051270
Ordering Recommendation
Diagnostic testing for galactosemia.
Mnemonic
GALTDNA FE
Methodology
Polymerase Chain Reaction/Single Nucleotide Extensions
Performed
Sun-Sat
Reported
5-7 days
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
 
Collect
Cultured cells: Two T-25 flasks at 80% confluent of cultured amniocytes. If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787.
Maternal specimen
: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).  
Specimen Preparation
Fetal Specimen: Fill flasks with culture media. Transport two T-25 flasks at 80% confluent of cultured amniocytes filled with culture media. Backup cultures must be retained at the client's institution until testing is complete.
Maternal Specimen:
Transport 3 mL whole blood.  
Storage/Transport Temperature
Fetal Specimen: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to lability of cells.
Maternal Specimen:
Room temperature.  
Unacceptable Conditions
 
Remarks
Maternal specimen is recommended for proper test interpretation. Order Maternal Cell Contamination. Patient History Forms are available on aruplab.com or by contacting ARUP Client Services.  
Stability
Fetal: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Maternal:
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable  
Reference Interval
By report
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 for classic galactosemia in Caucasians; 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.

For quality assurance purposes, ARUP Laboratories will confirm the above result at no charge following delivery. Order Confirmation of Fetal Testing and include a copy of the original fetal report (or the mother's name and date of birth) with the test submission. Please contact an ARUP genetic counselor at (800) 242-2787 extension 2141 prior to specimen submission.



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 a known familial mutation(s).
CPT Code(s)
81401; Fetal Cell Contamination (FCC): 81265
Components
Component Test Code*Component Chart Name
0050548Maternal Cell Contamination, Fetal Spec
0050612Maternal Cell Contam, Maternal Spec
0051177Galactosemia - Ethnicity
0051178Galactosemia - Symptoms
0051180Galactosemia - Family History
0051182Galactosemia (GALT) Allele 1
0051183Galactosemia (GALT) Allele 2
0051184Galactosemia (GALT) DNA Panel Interp
2001352Galactosemia (GALT) DNA Pan, Fetal Spec
* 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.
Cross References
  • Galactosemia Carrier Testing
  • Galactosemia Confirmation Test
  • Galactosemia genotyping
  • GALT DNA