Unverricht-Lundborg Disease

Unverricht-Lundborg disease (ULD) is the leading cause of progressive myoclonus epilepsy (characterized by brief, jerking spasms of a muscle or muscle group) worldwide.

Last Updated: February 23, 2024

The prevalence of Unverricht-Lundborg disease is unknown. However, in Finland, nearly four out of every one hundred thousand suffer from Unverricht-Lundborg disease.

A change in a gene called the CSTB gene is the cause of ULD. The CSTB gene tells the body how to make the protein cystatin B. This protein is vital to the way the brain works, especially the part of the brain called the cerebellum. In ULD, the different symptoms are caused by an abnormal protein called cystatin B.

  • Short, random contractions of the muscle that happen at rest, in reaction to sensory stimuli, or in combination with voluntary movement
  • Asynergy - a lack of coordination between muscles, limbs, and joints 
  • Dysmetria- inability to judge distances, which can cause grasping movements to undershoot or overshoot 
  • Dysdiadochokinesia- inability to perform rapid movements
  • Poor articulation in speech or difficult to understand
  • Appendicular ataxia- when an individual finds it difficult to touch a target such as his nose or a physician's finger
  • Dementia- loss of previously present cognitive abilities that affect memory, thinking, language, judgment, and behavior
  • Subnormal intelligence

Doctors will perform history taking, physical examination, and a focus on neurological physical exam to elicit the expected motor deficits.

Genetic testing is one of the most important tests to check if the patient has mutations in the CSTB gene.

EEG will also be ordered due to epilepsy, as the severity needs to be assessed. 

Magnetic resonance imaging (MRI) as patients who suffer from ULD was found to have atrophy in areas of the brain such as the cortical motor areas, the pons, the medulla, and the cerebellar hemispheres.

Treatment

Although no known treatment can guarantee a full recovery, many symptoms can be managed. The seizures and movement myoclonus caused by epilepsy can be managed with medication. Among these drugs are sodium valproate (Epilim), clonazepam (Rivotril), levetiracetam (Keppra), and topiramate (Topamax).

Young adults and adolescents with severe action myoclonus may benefit from piracetam, a separate class of medication. 

Lastly, the ketogenic diet has shown promise, particularly in reducing the frequency of seizures (both tonic-clonic and myoclonic).

Unfortunately, ULD is unpreventable; however, symptom control is the best management that doctors and experts offer presently.

 

References

Lehesjoki AE, Gardiner M. Progressive myoclonus epilepsy: Unverricht-Lundborg disease and Neuronal ceroid lipofuscinoses. In: Noebels JL, Avoli M, Rogawski MA, et al., editors. Jasper's Basic Mechanisms of the Epilepsies [Internet]. 4th edition. Bethesda (MD): National Center for Biotechnology Information (US); 2012. Available from: https://www.ncbi.nlm.nih.gov/books/NBK98154/

 

National Institutes of Health (2021). Unverricht-Lundborg disease. Retrieved December 27, 2022, from https://rarediseases.info.nih.gov/diseases/3876/unverricht-lundborg-disease/living

 

National Organization for Rare Diseases (2021). NIH GARD Information: Unverricht-Lundborg disease. Retrieved December 27, 2022, from https://rarediseases.org/gard-rare-disease/unverricht-lundborg-disease/

Last Updated: February 23, 2024