Rare epilepsies are illnesses that are diagnosed with less than one person in every 2,000 people. There are about 8,000 different rare illnesses. As we learn more about different illnesses, the number of rare illnesses keeps growing. When the disease or symptoms are rare, special expertise and a special concentration of treatment are needed in its diagnosis.
Some forms of epilepsies are considered rare. There are approximately 30 rare epilepsies. There are also around 140 other rare illnesses, where epilepsy is a prominent symptom.
Rare and severe epilepsies
Rare epilepsies are usually severe. Severe epilepsy is a state where regardless of proper medication, there are significant daily life limiting symptoms present, such as recurring seizures, cognitive or behavioural problems, decreased level of development or side effects of treatment.
There are around 9,000 people with severe epilepsy in Finland, which is about 20-25 % of all epilepsies. Severe epilepsy can occur at any stage in life, but most severe epilepsies begin in childhood.
Alongside with seizures, individuals with rare and severe epilepsies often face challenges in functioning and intellectual activity which can cause more harm than epileptic seizures.
Causes of rare epilepsies
There are different causes of rare and severe epilepsies. Some are known well but others are diagnosed based on typical features, such as type of seizure, the age of onset or the brain’s electrical curve.
Known reasons are dysfunctions of the brain’s development, brain damages or chromosome and genetic abnormality. Diagnostics improve continuously as gene research and the brain’s scanning procedures improve.
Examples of rare epilepsies
There are many rare epilepsies, such as:
- Progressive myoclonic epilepsy Type 1 (Unverricht-Lundborg disease)
- Infantile Spasm
- Dravet syndrome
- Lennox-Gastaut Syndrome
- Rasmussen Encephalitis
- Northern epilepsy syndrome
- Sturge-Weber Syndrome
- Landau-Kleffner Syndrome
Examples of rare epilepsy
Forms of rare and complex epilepsies include, for example, progressive myoclonic epilepsy type 1 (Unverricht-Lundborg disease, ULD-EPM1), infantile spasm syndrome, Dravet syndrome, Rasmussen's encephalitis, Northern epilepsy, Sturge-Weber syndrome and tuberculosis. In addition, there are a number of epilepsies associated with rare structural, inflammatory, and immunological causes, as well as epilepsy associated with rare chromosomal aberrations and genetic defects.
Information related to rare epilepsy has been compiled in Finnish on Health Village's (Terveyskylä) -website. At this stage, Health Village has diagnosis-specific information in Finnish on the following rare epilepsies: