Cost 
$1,000.00
TAT 
4 weeks
CPT Code 
81404
Test Code 
4112
Test Methods 
Deletion/Duplication analysis
Specimen Types Accepted 
Blood
Saliva
Cultured Cells
Extracted DNA
Notes 
If sending saliva, 2 kits are required.

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is characterized by infantile-onset epileptic encephalopathy associated with delayed development, acquired microcephaly, motor incoordination, and spasticity.  Seizures typically begin within the first 4 months of life following a normal birth and gestation.    Glucose concentration in cerebrospinal fluid should be the first test considered in patients suspected of having GLUT1DS.  Hypoglycorrhachia (low CSF glucose, less than 40mg/dl) is practically diagnostic for this disorder. Calculation of the ratio of CSF glucose concentration to blood glucose concentration is consistently about 0.33±0.01 (normal ratio: 0.65±0.01).    Mutations of the Solute Carrier Family 2, Member 1 (SLC2A1) have been identified in patients with GLUT1DS.  The SLC2A1 gene maps to 1q35 and has 10 coding exons.  Sequencing of SLC2A1 detects mutations in approximately 91% of affected individuals. Affected individuals with whole gene deletions of SLC2A1 have also been reported.  We offer deletion/duplication analysis of SLC2A1 by MLPA to identify deletions/duplications of one or more exons.  The sensitivity of our deletion/duplication assay may be reduced when DNA is extracted by an outside laboratory.