A rare X-linked syndromic intellectual disability disease characterized by neonatal hypertonia which evolves to hypotonia and an exaggerated startle response (to sudden visual auditory or tactile stimuli) followed by the development of early-onset frequently refractory tonic or myoclonic seizures. Progressive epileptic encephalopathy intellectual disability and psychomotor development arrest with subsequent decline may be additionally associated.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version June 2026
Newly diagnosed with
Hyperekplexia-epilepsy syndrome?
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Advocacy Organizations
Access to Life NGO
Our mission is to improve the lives of people affected by genetic epilepsies by empowering patients and families, advancing access to diagnosis and treatment, supporting research, and advocating for equitable, patient-centered care in Ukraine in alignment with global rare disease standards.
Genetic Epilepsy Team Australia
Collaboration of research and care
Rare Epilepsy Network (REN)
Improving outcomes of people with rare epilepsies through an innovative collaborative infrastructure that drives urgent, patient-centered research, educaiton and advocacy.
ReNU2 United
ReNU2 United fosters collaboration, supports families, raises awareness, and advances research into RNU2-2-related neurodevelopmental disease.
Uganda Alliance of Patients Organization
Supporting patients to access quality, safe and patient-centered healthcare services.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.