Short answer · Medically reviewed summary · Last updated: 2026-05-08
TL;DR: Unverricht-Lundborg disease (ULD), also known as EPM1, is a rare inherited form of progressive myoclonus epilepsy characterized by involuntary muscle jerks and generalized seizures. It is a chronic, slowly progressive neurological condition caused by mutations in the CSTB gene that affects the central nervous system. What are the symptoms and body systems affected by Unverricht-Lundborg disease? Unverricht-Lundborg disease primarily impacts the central nervous system.
What is Unverricht-Lundborg Disease
What is Unverricht-Lundborg Disease? Plain-language, medically reviewed definition plus the lived reality told by patients.
TL;DR: Unverricht-Lundborg disease (ULD), also known as EPM1, is a rare inherited form of progressive myoclonus epilepsy characterized by involuntary muscle jerks and generalized seizures. It is a chronic, slowly progressive neurological condition caused by mutations in the CSTB gene that affects the central nervous system.
What are the symptoms and body systems affected by Unverricht-Lundborg disease?
Unverricht-Lundborg disease primarily impacts the central nervous system. The hallmark symptom is stimulus-sensitive myoclonus—sudden, involuntary muscle contractions triggered by light, sound, or physical touch. Over time, individuals with Unverricht-Lundborg disease may experience ataxia (loss of balance and coordination), tremors, and generalized tonic-clonic seizures. Unlike some other forms of epilepsy, cognitive decline in Unverricht-Lundborg disease is generally mild or absent, though mood disturbances and difficulty with daily motor tasks are common.
How common is Unverricht-Lundborg disease and who does it affect?
Unverricht-Lundborg disease is an exceptionally rare condition with an estimated global prevalence of 1 in 20,000 to 1 in 50,000, though it is more frequently diagnosed in specific populations, such as those of Baltic or Mediterranean descent. Symptoms of Unverricht-Lundborg disease typically emerge between the ages of 6 and 15 in previously healthy children. The condition affects both males and females equally and is inherited in an autosomal recessive pattern, meaning an individual must inherit two copies of the mutated CSTB gene to develop the disease.
What distinguishes Unverricht-Lundborg disease from other epilepsy syndromes?
While many epilepsy syndromes are categorized by seizure type, Unverricht-Lundborg disease is unique due to its specific genetic cause and clinical progression. Key differentiating factors include:
- Genetic Origin: Caused by a repeat expansion in the CSTB gene, which leads to a deficiency of the protein cystatin B.
- Myoclonus Sensitivity: The jerks are notably exacerbated by external stimuli, a feature less common in other childhood epilepsies.
- Slow Progression: Unlike other progressive myoclonus epilepsies (like Lafora disease), Unverricht-Lundborg disease typically follows a slower, more stable clinical course.
Next steps
- Consult a neurologist specializing in epilepsy or a clinical geneticist to discuss diagnostic testing.
- Connect with the 19 community members on DiseaseMaps.org who are currently living with Unverricht-Lundborg disease to share experiences.
- Maintain a detailed seizure and symptom journal to help your care team optimize your treatment plan.
Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases (GARD) Information Center: Unverricht-Lundborg disease.
- Orphanet: Progressive myoclonus epilepsy type 1 (EPM1).
- OMIM (Online Mendelian Inheritance in Man): Entry #254800 (EPM1A).
