New research from the University of California San Francisco, US, has identified a gene alteration linked to both migraines and a sleep disorder.
Migraine is a complicated disorder characterized by severe headache and sensitivity to light and sound. In some instances it can cause nausea and vomiting. Migraine affects over 10% of the world's population, which amounts to a staggering 700 million people, according to reports by the National Institute of Neurological disorders and Stroke of the United States.
For several years, scientists and doctors have believed that the constriction and dilation of brain blood vessels must be responsible for the migraine episodes, but there is still no known cure for migraine. The main reason is that, although physicians have always tried to address the symptoms, the cause of migraine remains poorly understood. Frequent doctor visits result in prescription of pain killers to obtain relief from migraine, which leads to rising health costs, loss of productivity at the workplace and inefficient use of a doctor's time. It has become imperative to the medical community to explore the physiological mechanisms of migraine and figure out what is the main cause of the disorder.
In the new study, which was published in the journal Science Translational Medicine, Louis Ptacek and colleagues used genetics to explain the cause of migraine attacks. They sequenced the genome of several members from two families who suffered from migraines and from a sleep disorder known as familial advanced sleep phase syndrome (FASPS). They found an alteration in a gene called casein kinase I (CKI) in all the affected members from both families. CKI is a gene involved in controlling the body's circadian rhythm - a sort of biological clock that determines our sleeping and feeding patterns.
Circadian rhythm disruption in patients with FASPS leads to an abnormal sleep pattern; the patients become early risers and as a result they feel sleepy very early in the evening. This kind of sleep disorder is inherited, which means that if one of the parents suffers from FASPS, there is a 50% probability of passing it on to the offspring.
The most exciting part of Ptacek's discovery is that FASPS and migraine are quite intricately linked, since the same alteration in the CKI gene causes both disorders. Genetically engineered mouse models lacking this gene, which have symptoms similar to human FASPS, were also more sensitive to pain.
This study provides a very rare and promising insight into the genetics of migraine. One of the biggest misconceptions about this disorder is that it is just a mere headache. On the contrary, it is a severe neurological disorder with a whole range of physical and emotional stress. An important consequence of these new findings is that more scientists may be motivated to further probe into other genetic alterations and neurobiological mechanisms contributing to migraine, which in the long run could lead to better treatments.