Overview
STXBP1-related disorder (sometimes called STXBP1 encephalopathy) is caused by a change, or variant, in the STXBP1 gene. This gene provides instructions for a protein essential to how brain cells communicate with one another. When it doesn't work as expected, it can affect a child's development, movement and how their brain regulates electrical activity — which is why epilepsy is common.
The condition is rare — thought to affect around 1 in 30,000 births — and sits on a wide spectrum. Two children with the same genetic variant can present very differently, which makes STXBP1 difficult for families and clinicians alike to plan around with certainty.
Symptoms
Symptoms vary widely, but commonly include:
- Seizures, often starting in infancy and varying in type and severity
- Developmental delay affecting speech, movement and learning
- Low muscle tone (hypotonia) and difficulties with coordination
- Movement disorders, including tremor or dystonia
- Sleep difficulties and sensory sensitivities
Not every child experiences every symptom, and severity ranges from mild to profound. Many children also have real strengths — sociability, a strong sense of humour, and determination — that are just as much part of the STXBP1 picture.
Diagnosis
Diagnosis is usually made through genetic testing — often whole exome or genome sequencing — prompted by unexplained seizures or developmental delay in infancy. Because STXBP1 is rare and relatively recently characterised (first described in 2008), many families are the first case their clinical team has encountered.
If you've just received a diagnosis, you are not alone, and it's normal to feel overwhelmed. Our resources page has guides written specifically for newly diagnosed families.
Treatment & care
There is currently no cure for STXBP1-related disorder, and care is tailored to each child's symptoms — typically involving a mix of anti-seizure medication, physiotherapy, occupational therapy, speech and language therapy, and educational support. A multidisciplinary team, often coordinated through a paediatric neurologist, is the usual model of care in the UK.
Research
Research into STXBP1 is moving quickly, including natural history studies to understand how the condition changes over time, and early-stage work towards targeted genetic therapies. STXBP1 UK Foundation funds and champions this research and works with international partners to keep UK families informed and represented.