Normal Function
The STXBP1 gene provides instructions for making syntaxin-binding protein 1. In nerve cells (neurons), this protein helps regulate the release of chemical messengers called neurotransmitters from compartments known as synaptic vesicles. The release of neurotransmitters relays signals between neurons and is critical for normal brain function.
To release its neurotransmitters, a synaptic vesicle must join (fuse) with the outer membrane of the neuron. The syntaxin-binding protein 1 regulates the formation of a group (complex) of proteins that allows vesicle fusion.
Syntaxin-binding protein 1 may also have a role in the positioning and growth of neurons during brain development. Proper localization of neurons is important for normal brain formation and function.
Health Conditions Related to Genetic Changes
STXBP1 encephalopathy
More than 150 mutations in the STXBP1 gene have been found to cause STXBP1 encephalopathy. This condition is characterized by abnormal brain function (encephalopathy) and intellectual disability. Most affected individuals also have recurrent seizures (epilepsy) that begin in infancy. The STXBP1 gene mutations can alter the structure of syntaxin-binding protein 1, result in an abnormally short protein, or add or delete small sections of the protein.
The gene mutations that cause STXBP1 encephalopathy reduce the amount of functional syntaxin-binding protein 1 produced from the gene. A shortage of this protein impairs the formation of the protein complex that allows vesicle fusion and the release of neurotransmitters from neurons. A change in neurotransmitter levels can lead to uncontrolled activation (excitation) of neurons, which causes seizures. Researchers suspect that a shortage of syntaxin-binding protein 1 also impairs neuron development in certain regions of the brain, which could underlie abnormal brain function and other neurological problems in people with STXBP1 encephalopathy.
More About This Health ConditionLennox-Gastaut syndrome
MedlinePlus Genetics provides information about Lennox-Gastaut syndrome
More About This Health ConditionOther Names for This Gene
- hUNC18
- MUNC18-1
- N-Sec1
- neuronal SEC1
- NSEC1
- RBSEC1
- unc-18A
- UNC18
- unc18-1
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
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- Yamamoto T, Shimojima K, Yano T, Ueda Y, Takayama R, Ikeda H, Imai K. Loss-of-function mutations of STXBP1 in patients with epileptic encephalopathy. Brain Dev. 2016 Mar;38(3):280-4. doi: 10.1016/j.braindev.2015.09.004. Epub 2015 Sep 16. Citation on PubMed
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