IEC 2023 | The prevalence of rare diseases associated with epilepsy

What is a rare disease? A rare disease is one which 1 in 2000 persons at maximum suffer from. Epilepsy as a whole is a common disease, between 0.6 and 1% of the population in the Western countries suffer from epilepsy. So, it’s very common. On the other hand, there are so many different etiologies and so many different comorbidities in persons with epilepsy that you could see epilepsy as a sum of rare diseases. So why is it important to know if somebody suffers from a rare disease? There are several aspects, one is this may enable you to tailor the treatment for this person. For instance, if you find a rare disease with a genetic origin, then you may be able to find drug treatment in the sense of precision medicine. The other thing is rare diseases have a meaning for self-advocacy in patients because there are so many self-advocacy associations for different rare diseases and there are certainly more to come. It also has a political dimension because many governments are in the process of paying more attention to patients with rare diseases. So, many university hospitals have centers for rare diseases, for instance, and rare diseases also have an importance in the allocation of research funding.

Having said that, I would like to tell you a little bit more about epilepsy centers in the German speaking countries. Certainly, that’s not restricted to the German speaking countries, it’s similar in a couple of other European countries. There are epilepsy centers at the university hospitals and these centers are those who gather in associations for the research on rare diseases in epilepsy. On the other hand, there are several traditional epilepsy centers, they have their origins in the 19th century, most of them are foundations from the Protestant church, so they come from a Christian tradition. They have a strong academic interest, but they are not university hospitals, or at least they have not a university tradition. For instance, looking at our hospital, the Bethel Epilepsy Center in Bielefeld, Germany, we have been appointed a university hospital around 2.5 years ago, but our history is more than 150 years old. These traditional epilepsy centers care for many persons with epilepsy and probably with rare diseases with a comprehensive care perspective.

So, we undertook this study in three of these traditional epilepsy centers in Germany and Switzerland. The Epilepsy Center Kehl-Kork in the south-west of Germany, and the Swiss Epilepsy Center in Zurich, Switzerland, and our center Bethel Epilepsy Center in Bielefeld, Germany. So, we picked by random one week in the year of 2021 and we searched our databases for the prevalence of rare diseases within this given week.

In total, we were able to include 504 patients, a little bit less than half of them females, and 44% of these 504 patients (222 patients) suffered from a rare disease, according to the Orphanet definition. We had patients with mesial temporal sclerosis. You could argue as a criticism, well, I didn’t think mesial temporal sclerosis is a rare disease, but it is one according to the definition of the Orphanet system, which we normally use. Then there are a few of the genetically determined syndromes like Dravet syndrome (DS) and tuberous sclerosis complex. There is also the Lennox-Gastaut syndrome, one of the top diagnoses of rare diseases in this week. Others I would like to mention are the juvenile myoclonic epilepsy as a form of idiopathic generalized epilepsy, isolated focal cortical dysplasia, and a couple of other diseases. In conclusion, we found that rare diseases are highly prevalent among the patients of traditional epilepsy centers and besides the meaning for the individual patient, we think that these centers should play a role within the research organizations and associations for rare diseases and should be considered for research funding.