Conception: Twenty three chromosomes from the mother join twenty three chromosomes from the father. At this moment, the genetic code of a human being is formed and will remain throughout that person’s life.
Your genetic background determines more than the color of your eyes, your height, and your potential for developing certain diseases such as diabetes. It also determines all the chemicals and structures that make up your brain. While these are similar in different people, they vary in certain enzymes and receptors.
Think, for example about the nose. Everybody has one, and everyone used it to breath. Noses vary, however, in structures. This makes them look somewhat different and also changes the amount of air that can be moved through nose. Most of the time, the variation in air movement between people is not a problem, but occasionally someone’s nose is so small or formed in such a way that the person has trouble breathing, and it needs to be corrected.
Perhaps in a similar way, genetics determines all the structures needed to build neurons, synthesize transmitters, and release them when a neuron is active. The slight variations in these form person to person don’t usually result in a problem, but sometimes a combination of factores make neurons overactive and cause epilepsy, but if it occurs in the same person as a change in the receptor, enough over activity may result to cause spontaneous seizures.
A number of types of epilepsy are genetic, and thus the potential for seizures is present from the time of conception. Not surprisingly, most of these people begin to have seizures during childhood. Most of these, as far as we know, are generalized epilepsies.
The exact genetic problems are not known as yet, but many will likely be found in the next years of decades. The epilepsy seizure types seen in these syndromes, however, are varied. Juvenile myoclonic epilepsy, for example has many distinct epilepsy seizure types absence staring spells, sudden myoclonic jerks, and generalized tonic clonic convulsions.
Yet this syndrome arises from a single mutation. Somehow, with a single tiny change in an ion channel, a receptor, or an enzyme in the brain, varied random irritability’s become manifest as seizures. Even in this people, the genetics are not simple.
At most, the chances of a child born of a mother or father with JME having epilepsy are about 10 percent. This leads us to suspect that probably not just one gene is involved, a combination of other factors must ultimately result in epilepsy. This complexity may be one reason why it has been so difficult to determine specific causes of genetic epilepsy.