Updated: Jan 19
About STXBP1 Disorder
STXBP1 Disorder is a rare developmental epileptic encephalopathy caused by mutations in the STXBP1 gene. The STXBP1 gene is located on chromosome 9q34.1 and was discovered in 2008 in studies of some patients with Ohtahara Syndrome, a severe early onset epilepsy. Since this initial discovery, our understanding of STXBP1 disorder has expanded, revealing a range of patient symptoms in varying severities, including: epilepsy, global delay, cognitive impairment, autism, and movement disorders. Symptoms overlap with many other rare neurodevelopmental conditions, which can result in misdiagnosis or delayed diagnosis. STXBP1 changes impact communication between nerves by impairing the vesicular release of neurotransmitter along the synapses. The estimated incidence rate for STXBP1 disorder is ~1:30,000, and STXBP1 was recently identified as one of the five most common genes for epileptic encephalopathies and related neurodevelopmental disorders (López-Rivera, J.A., et al, 2020, Symonds and Mctague, 2019).
STXBP1 Disorder Clinical Features
For STXBP1 patients, seizures are a dominant feature and often the first manifestation of the condition. ~85% of patients presenting with seizures (Abramov et al, 2020). For other patients, developmental delay may be the first sign. The patient population is heterogeneous, and patients may have the same STXBP1 variant but variability in symptoms. Beyond seizures, patients may present with global delay, cognitive impairment (mild to profound), behavior disorders including autism, movement disorders, hypo- or hypertonia, feeding difficulties and communication challenges. There are no precision treatments for STXBP1 disorders. Typical treatment for seizures is antiepileptic drugs, and 25% of patients are refractory to AED therapy.
Get to Know STXBP1 Foundation
The STXBP1 Foundation is a parent-led advocacy organization. Founded by five families in 2017, we are dedicated to building awareness, and accelerating therapies and hopefully a cure for STXBP1 disorders. To accomplish our mission, we collaborate with and fund researchers to speed development of therapies and therapeutic approaches. The STXBP1 Foundation is based in the US, and works with researchers and patients worldwide.
I am especially proud of ...
In 2019, we hosted our first STXBP1 Investigator and Family Meeting, and we were delighted that over 200 people attended - 60 families and 40 researchers. At that meeting, we shared updates on new research and developed a research roadmap to guide priorities going forward. Despite all of the surprises and challenges that 2020 has brought, we are excited that we will launch the first clinical trial for STXBP1 with our collaborators at Weill-Cornell by the end of the year.
Excited to REN because...
We are excited to collaborate with the REN advocacy groups to amplify and support each other as we work to build a better future for our patients. Across the rare epilepsy groups, there is knowledge, experience and even battle scars we can all learn from. Better for us to collaborate so we can go farther for our collective patient community, instead of reinventing the wheel for each rare disease.
My journey and motivation...
My daughter, Juno, has an STXBP1 disorder. She was diagnosed through whole exome sequencing after a three-year journey and many, many tests. Over that three year period as test after test came back negative, I convinced myself that she might just be developing very slowly and on her own schedule. The diagnosis was admittedly a shock, but I realized that I could help to make a difference for Juno and for patients like her. I am extremely motivated to do this for our patient community.
By Charlene Son Rigby, President and Cofounder of the STXBP1 Foundation