Collect whole blood in a purple top (EDTA) tube (preferred).
Extracted DNA is also acceptable.
5 ml whole blood or 3 ug extracted DNA
Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.
Whole blood can be refrigerated until shipment.
Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.
Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.
Mon - Fri 9:00am to 4:00pm
4 - 5 weeks
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.
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.
We offer DNA sequence analysis of the entire coding region including splice junctions. PCR amplification and sequencing is performed on the coding region. The patient’s gene sequence is then compared to a reference sequence. Sequence variants are classified as mutations, variants of unknown significance or benign variants unrelated to disease. Variants of unknown significance may warrant further studies in the patient and other family members. Large deletions, mutations in promoters, deep intronic regions and other regulatory regions will not be identified with this assay.
Sequence analysis of the SLC2A1 gene will detect mutations in 90% of affected individuals. The analytical sensitivity of this assay is 99%.
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.
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.
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.
Whole blood in EDTA purple top tubes is the preferred sample. High molecular weight genomic DNA is also acceptable. 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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