4 weeks
CPT Code 
Test Code 
Test Methods 
Deletion/Duplication analysis
Specimen Types Accepted 
Cultured Cells
Extracted DNA
If sending saliva, 2 kits are required.

Mutations of the Syntaxin binding protein 1 (STXBP1) have been identified in patients with early infantile epileptic encephalopathy 4 (EIEE4). The STXBP1 gene maps to 9q34.1 and has 19 coding exons. Syntaxin binding protein 1, more commonly referred to as MUNC18-1, is a neuron specific protein of the SEC1 family of membrane-trafficking proteins. MUNC18-1 is expressed throughout the brain and is a key component for calcium-dependent neurotransmitter release. Sequencing of STXBP1 detected mutations in 4 out of 106 patients with EIEE. Earlier reports identified 4 heterozygous missense mutations in 13 patients with EIEE. Affected individuals with microdeletions involving STXBP1 have also been reported. Deletions and/or duplications of the STXBP1 gene as causative of epileptic encephalopathy have been reported. STXBP1 deletion/duplication is available as an individual test or as part of our Early Infantile Epileptic Encephalopathy (EIEE) panel. Please see our information sheet for more details.