Is Unverricht-Lundborg Disease hereditary?

Unverricht-Lundborg disease is a hereditary condition, meaning it is passed down through families via genetic mutations rather than being acquired later in life. It follows an autosomal recessive inheritance pattern, which means an individual must inherit two copies of the mutated gene—one from each parent—to develop the disease.

Is Unverricht-Lundborg disease strictly hereditary?

Yes, Unverricht-Lundborg disease (EPM1) is a strictly hereditary genetic disorder caused by mutations in the CSTB gene. Because it is autosomal recessive, the parents of an affected child are typically asymptomatic carriers, each carrying one copy of the mutated gene. De novo (spontaneous) mutations are extremely rare in Unverricht-Lundborg disease, as nearly all cases result from inherited genetic variants.

What is the risk of inheritance for family members?

When both parents are carriers of a CSTB mutation, the risk profile for their children is as follows:

• 25% chance for each child to inherit two mutated genes and develop Unverricht-Lundborg disease.


• 50% chance for each child to be an asymptomatic carrier like the parents.


• 25% chance for each child to inherit no mutated genes and be neither affected nor a carrier.

How is genetic testing utilized for this condition?

Genetic testing is the gold standard for confirming a diagnosis of Unverricht-Lundborg disease. Clinical geneticists recommend testing for individuals presenting with stimulus-sensitive myoclonus and tonic-clonic seizures. Because Unverricht-Lundborg disease is rare, molecular confirmation is essential for accurate prognosis and family planning. Genetic counseling is highly recommended to help families understand the inheritance risks and explore options such as carrier screening for siblings or reproductive testing.

Are there options for prenatal or family planning?

For families with a known history of Unverricht-Lundborg disease, prenatal diagnosis (via chorionic villus sampling or amniocentesis) and preimplantation genetic testing (PGT) are available. These options allow parents to identify the presence of the CSTB mutations in embryos or fetuses, providing critical information for family planning decisions.

Next steps

• Consult a clinical geneticist to discuss diagnostic testing and familial risk assessment.


• Connect with the 19 members of the Unverricht-Lundborg disease community on DiseaseMaps.org to share experiences.


• Seek a referral to a neurologist specializing in progressive myoclonus epilepsies.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Unverricht-Lundborg disease.


• Orphanet: EPM1 (Unverricht-Lundborg disease).


• OMIM (Online Mendelian Inheritance in Man): Entry #254800 (EPM1A).