Information for patients

This page is written to provide background information on STXBP1-Encephalopathy, intended for patient families and others interested in the basic principles of this disease.

What is STXBP1 Encephalopathy?

STXBP1 is one of the many thousands of genes in our DNA. In 2008, researchers concluded that small changes in the DNA sequence (mutations) of this gene cause Ohtahara syndrome (Saitsu et al., 2008). Since then, more reports have come out identifying STXBP1 mutations as a cause for several other neurodevelopmental diseases (see figure below). Collectively, these diseases are now called STXBP1 Encephalopathy or STXBP1-E (most of these reports are nicely summarized in the review paper Stamberger et al., 2016).

Symptoms

Patients with an STXBP1 mutation can experience a variety of symptoms. The most characteristic symptoms are intellectual disability and epilepsy (95% of the patients), but many patients suffer from additional symptoms, such as movement disorders (e.g. muscle hypotonia, ataxia) or neuropsychiatric features such as autism spectrum disorder.

Incidence

Mutations in STXBP1 are rare. A recent estimation (based on the Danish population) is that 1 in approximately 90.000 children is affected by a disease-causing change in STXBP1 (Stamberger et al., 2016). Patients are diagnosed by genetic testing after visiting a clinic, typically soon after birth.

Treatment

To date, there is no therapy known that treats STXBP1-E patients beyond symptomatic treatments, for example using antiepileptic drugs. Providing new strategies for developing therapies for STXBP1 patients is another long-term goal in our research.


About the nature of STXBP1 mutations

STXBP1 Encephalopathy is typically caused by a heterozygous mutation

Humans, as well as most animals and plants, have two copies of each of their genes. STXBP1-E patients generally have a mutation only in one of the two copies, while the other copy is unaffected. This is called a heterozygous mutation.

STXBP1 mutations are typically ‘de novo’

STXBP1 disorders typically arise in families ‘de novo’ (Latin for ‘new’). This means that the mutation in the STXBP1 gene occurs for the first time in the affected patient, and is not present in the (grand)parents. Instead, when a mutation is de novo, the mutation has occurred spontaneously and randomly in the germ cells of one of the parents or in the fertilized egg. Every person carries many de novo mutations, but very often these mutations are not in essential parts of our DNA and do not affect our health. It is relatively rare that de novo mutations occur in an essential part of our DNA and that a single mutation has a large impact on our health, as is the case for STXBP1 mutations.

Links to external webpages and online communities for STXBP1-E

STXBP1 disorders foundation: The STXBP1 disorders foundation, based in the USA, is dedicated to raising awareness of STXBP1-E among parents, physicians, scientists, and pharmaceutical innovators. The foundation was created by a group of dedicated parents. They are focused on advocacy, driving research, and providing the families and their physicians with information and resources. We work together with the foundation to increase awareness and to provide resources to the STXBP1-E community. Please visit their website for more information and events.

German STXBP1 website: https://stxbp1.de

Spanish STXBP1 website: https://stxbp1.es

Dutch facebook group: facebook.com/Stxbp1GeneticDisorder

Get in touch with us

We hope to gather information about STXBP1 mutations observed in patients and their symptoms from many STXBP1-E patients. We work with local clinicians as well as with clinicians worldwide to gather such information and we are very interested to get in touch with patients carrying an STXBP1 mutation and their caregivers. If you are interested in our research and would like to know how you can help further it, please send us an email at stxbp1@amsterdamumc.nl.

Reference list primary clinical diagnoses

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