STXBP1 Encephalopathy

Original research article by Stamberger et al. (2016).

Read the abstract here.

The STXBP1 gene has a role in brain signaling and is most commonly linked with Ohtahara syndrome, a syndrome characterized by seizures and EEG (electroencephalograms) abnormalities presenting in infancy. As access to and uptake of genetic testing has increased, researchers have identified new gene changes (mutations) in the STXBP1 gene, allowing us to broaden our understanding of the range of features associated with STXBP1.

In this article, Dr. Stamberger and her team identified 45 individuals with STXBP1 mutations through research and diagnostic populations. They performed a literature review of current STXBP1 research and compared the observed features in the newly-identified 45 individuals with 102 other individuals with STXBP1 mutations who were previously published in other research articles.

Ranging from 6 months to 56 years in age, researchers compared diagnoses (see below) and features observed in the 147 individuals with STXBP1 mutations. All 147 individuals were reported as having some degree of intellectual disability (ID), with approximately 88.4% categorized as severe or profound ID. The majority of individuals (approximately 95%) were found to have an epilepsy-related diagnosis, with onset early in life, which likely prompted genetic testing in the first place. Over 60% of those diagnosed with a form of epilepsy have a history of abnormal EEGs. Autism was observed in approximately 1 in 5 individuals and impaired or delayed motor functioning were frequently reported.

STXBP1-Associated Diagnoses Seen in 147 Individuals
Diagnosis	Percentage of Individuals with Diagnosis (%)
Early-onset epileptic encephalopathy (EOEE)	53
Ohtahara Syndrome	21
West Syndrome	10
Intellectual Disability (ID) without epilepsy	7
Intellectual Disability (ID) with epilepsy	6
Dravet Syndrome	2
Early myoclonic encephalopathy (EME)	1