What is Northern Epilepsy?
Northern epilepsy is an inherited disease that causes seizures and leads to severe mental disability in adulthood.
Children with Northern epilepsy appear normal until they begin to develop seizures between the ages of 5 and 10. The seizures increase in frequency until puberty, after which they decline in frequency, but do not disappear. Within 2 to 5 years of the first seizure, the child begins to decline mentally. This decline is progressive and by the age of 30, the person is mentally disabled (an IQ less than 70), regardless of whether the seizures were controlled by medication. After age 30, people with the disease may also become clumsy in their movements and have problems with balance.
One third of people with the disease will also develop mild loss of visual acuity in adulthood.
Northern epilepsy belongs to a heterogenous group of diseases known as neuronal ceroid lipofuscinoses. Northern epilepsy is caused by a mutation in the gene CLN8. This gene carries the instructions for a particular protein, but the function of this protein is unknown.
How common is Northern Epilepsy?
In Finland, 1 in 135 people are carriers of the disease. All cases to date have been among Finnish people, particularly in the northern part of the country. Fewer than 50 cases have been described in the medical literature.
How is Northern Epilepsy treated?
There is no effective treatment for Northern epilepsy. Seizures can be controlled with medication, however this will not slow the progression of the disease towards mental disability.
What is the prognosis for a person with Northern Epilepsy?
People with Northern epilepsy often live to the age of 50 or 60, but have significant mental and physical impairments for much of their lives.