North Sea-Progressive Myoclonus Epilepsy
North Sea-Progressive Myoclonus Epilepsy
North Sea-Progressive Myoclonus Epilepsy (NS-PME) is a rare, inherited disorder caused by a mutation in the GOSR2 gene. Patients develop symptoms at an early age, including balance problems (ataxia), disabling involuntary muscle jerks (myoclonus), and epilepsy. All known patients have ancestry tracing back to countries around the North Sea, likely originating from Friesland. The disease was only identified in 2011, and due to its rarity, limited information was available.
In her dissertation, Sjoukje Polet investigated the disease course, quality of life and underlying disease mechanisms of NS-PME. Retrospective chart reviews and questionnaires revealed a typical clinical sequence: ataxia around the age of 2, myoclonus around age 5, and epilepsy typically before the age of 10. Despite this typical sequence, symptom severity and progression varied among patients. Notably, heat was identified as a significant factor exacerbating symptoms.
The second part of the dissertation focused on quality of life. Interviews with patients and families revealed that QoL is primarily determined by independence, autonomy, social interactions, and personal fulfillment. These factors are not adequately captured by standard quality-of-life questionnaires.
Finally, Polet explored the disease mechanism using a Drosophila Melanogaster (fruit fly) model. This model showed that glial cells, the supportive cells of the nervous system, play a crucial role in the pathogenesis. Furthermore, GABA-A receptor-stimulating anti-epileptic drugs significantly reduced seizure activity in the model.
In summary, this dissertation provides valuable insights into the disease course, key factors influencing quality of life, and potential starting points for future therapeutic research in NS-PME.