4 weeks
CPT Code 
Test Code 
Test Methods 
Specimen Types Accepted 
Cultured Cells
Extracted DNA

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. We offer full gene sequencing of all 19 coding exons and intron/exon boundaries of STXBP1 by direct sequencing of amplification products in both the forward and reverse directions. STXBP1 sequencing is also available as part of our Early Infantile Epileptic Encephalopathy (EIEE) panel, and our Autosomal Recessive and Comprehensive Intellectual Disability Panels. Please see our information sheets for more details.