Summary: Researchers identify genetic factors that protect from the chronification of migraines.
Source: Kazan Federal University
According to existing estimates, migraine is a highly prevalent ailment, with about 15 percent of global population suffering from it at one time or another. In Russia, the ratio is as high as 20 percent. The current diagnostics and treatment methods are strictly clinical, i. e. they are based on a patient’s complaints.
This research was conducted by KFU’s Neurobiology Lab and Gene and Cell Technologies Lab. The team looked for genetic markers of migraine for about two years. Colleagues from Saint-Petersburg and Kazan State Medical University also contributed.
“Chronic migraine is a much more serious disease than episodic migraine. Migraine is prone to becoming a chronic syndrome, so it’s important to detect those who may become afflicted in the risk groups with episodic migraines. Such patients may be assigned prevention medications to avoid chronic migraine. Thanks to this particular research, we found genetic factors protecting from the chronification of migraines,” says neurologist, Junior Research Associate Aliya Yakubova.
For the testing, 46 patients with migraine and 50 patients without the disease were selected. They donated blood for DNA sequencing. In the sequencing process, the scientists determined polymorphisms in the pain receptor TRPV1. In this case, the replacement of nucleotide A by nucleotide G leads to the change in amino acids.
At this stage, the pilot studies have been completed. The selection process will continue, and patients with chronic or episodic migraine can partake.
“We will test the results on a larger selection of individuals. If our takeaways stand ground, we’d like to introduce them into clinical practice. If a patient has genotypes AA or AG, which don’t prevent migraine chronicity, they can receive long-term prevention therapies. If they have the GG genotype, chronicity is unlikely, and only symptomatic therapy can be prescribed,” continues Yakubova.
The work helped find significant differences in polymorphisms in patients with chronic versus episodic migraine. This means that some degree of genetic predisposition exists, and there are risk factors and prevention factors of chronicity for all the three genotypes. The patenting process for the technique is currently underway.
Searching for Predictors of Migraine Chronification: a Pilot Study of 1911A>G Polymorphism of TRPV1 Gene in Episodic Versus Chronic Migraine
Transient receptor potential vanilloid type 1 (TRPV1) receptors activated by heat and capsaicin are expressed in trigeminal nociceptive neurons and implicated in the generation of migraine pain. Genetic studies suggested that single-nucleotide polymorphism (SNP) 1911A>G (rs8065080), leading to amino acid substitution Ile585Val, in the TRPV1 gene affects functional activity of TRPV1 receptors and is involved in different pain conditions. However, this polymorphism has not been tested in migraine patients. The objective of this pilot study was to investigate genetic factors of migraine susceptibility. We evaluated frequency distribution of AA, AG, and GG variants of SNP 1911A>G in the TRPV1 gene in patients with episodic and chronic migraine compared with healthy individuals. The study included 46 patients diagnosed with migraine (27 episodic and 19 chronic) and 50 healthy individuals as a control group. DNA from peripheral blood was used to test TRPV1 SNP using allele-specific PCR combined with gel electrophoresis. The genotype frequency distribution in episodic migraine was comparable with that in controls (AA 33%, AG 56%, GG 11% and AA 34%, AG 46%, GG 20%, respectively). On the contrary, in chronic migraine, the distribution differed significantly (p < 0.05) (AA 68%, AG 32%, GG 0%). This are first indications for a distinctive genotype frequency distribution of TRPV1 1911A>G in chronic migraine patients compared with episodic migraine patients and controls. Our data confirm a different predisposition to chronic pain in migraine and give a prerequisite for a new look at the nature of chronification of migraine, proposing that the absence of GG genotype may be considered as possible risk biomarker of episodic migraine evolution to chronic form.