Migraine is a complex genetic condition. A complex genetic condition is one where you need to have the underlying genetic variations to get the condition, but there is something else in our bodies or the environment that brings on the negative symptoms.
Migraine is caused by a number of different genetic variations, in most cases a number of different gene variations combining, that relate to the ion channels in the brain or something that affects the ion channels in the brain. Ion channel or transporter genes move salts around the brain. They are important because they can determine how easily activated our nerves are and how they might react when stimulated. In recent years, it has become very clear that migraine is mainly a disorder of the nervous system. It is not, as had been thought for a long time, a disorder of blood vessels or a problem with inflammation.
A very consistent finding in people with migraine is an increased responsiveness of the nervous system to stimulation, even between attacks. Since ion channels determine nerve excitability, we can immediately see how defects in their genes could also explain why the nervous systems of people with migraine are more excitable. It is believed the ions travel through a migraine brain faster than in the brain of someone who doesn't have migraine, making the migraine brain hyper-reactive. When exposed to our triggers - which are unique to each person but range from food chemicals, to smells, to hormones – those ions go too fast, the valve that normally regulates the ion channels gets stuck open, and the brain overloads resulting in the migraine attack.
The concept of migraine as a genetic disorder is still a relatively new idea in medical science. Early research indicated that aura migraines were more commonly hereditary, and certain rare types such as Hemiplegic Migraine were strongly genetic with just a single gene variation causing the disorder. More recent research suggests that migraine without aura can also have a strong family history and is clearly genetic. The science has now largely settled, since the discovery of the TRESK gene in 2010, that all migraine has a genetic basis. There are now over 130 regions of our DNA implicated in causing migraine.
Much of the research into the genetic basis of migraine has been led by Queensland University of Technology researcher Distinguished Professor Lyn Griffiths. In this video, she talks to the Australian Academy of Science about migraine and genetics.