Glucose Transporter type 1 Deficiency Syndrome (SLC2A1)Deletion/Duplication Analysis
- Synonyms: GLUT1, GLUT1-DS
- LIS Mnemonic: MBSLC2A1DEL
Collect
Collect whole blood in a purple top (EDTA) tube.
Volume Required
5ml
Minimum Required
3ml
Transport
Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.
Stability
Whole blood can be refrigerated until shipment.
Unacceptable conditions
Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.
Specimen Handling
Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.
Days Performed
Mon - Fri 9:00am to 4:00pm
Reported
4-6 weeks
CPT
81479
Disease Information
Clinical Features:
Glucose transporter type 1 deficiency syndrome (Glut1-DS) is an autosomal dominant disorder characterized by reduced transport of glucose in to the brain. Affected patients present with infantile-onset epileptic encephalopathy associated with delayed neurologic development, acquired microcephaly, ataxia, dystonia and spasticity. Patients with atypical phenotypes present with developmental delay and movement disorders without epilepsy. The diagnosis of Glut1-DS is established with a reduced cerebrospinal fluid (CSF) glucose concentration (hypoglycorrhachia) in the absence of hypoglycemia and low ratio of CSF glucose concentration to blood glucose concentration.
Molecular Genetics:
SLC2A1 (solute carrier family 2, facilitated glucose transporter member 1) is the only gene currently known to be associated with Glut1-DS. Sequence analysis of the SLC2A1 gene will detect mutations in approximately 90% of affected individuals. Whole gene deletions have been reported in 10% of patients. Mutations are most often de novo although a few affected parents have been identified. Parents can be mildly affected.
Test Methods:
Large deletions and duplications in the SLC2A1 gene are detected using multiplex ligation-dependent probe amplification assay (MLPA).
Detection Rate:
MLPA of the SLC2A1 gene will detect deletions/duplications in 10% of affected individuals. The analytical sensitivity of this assay is 99%.
Related Tests:
Known mutation analysis is available to family members for mutations previously identified by sequence analysis.
Prenatal testing is available for families in whom a mutation has been previously identified. Please contact the laboratory director to discuss appropriate testing prior to collecting a prenatal specimen.
Results:
Test results with interpretation will be mailed and/or faxed to the referring physician or laboratory following completion of the test. Additional reports will be provided as requested.
Utility:
The clinical utility of such testing is to support a clinical diagnosis of the disease, facilitate genetic counseling, assess the risk to other first degree relatives and to facilitate testing of at - risk family members.
Remarks
Whole blood in EDTA purple top tubes is the preferred sample. High molecular weight genomic DNA, cheek epithelial cells, or other samples containing DNA may be acceptable. Contact the laboratory for specific instructions regarding such samples before sending the sample.
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