Evidence Shows Genetic, Epigenetic Factors May Be Responsible for Migraine Transformation

Individuals’ susceptibility to genetic and epigenetic factors may be responsible for the transformation of episodic migraine to chronic migraine in some patients, according to a new review published in The Journal of Headache and Pain.

Migraine is a life span disorder and affects about 15% of the general population. According to the World Health Organization, migraine is the most prevalent, disabling, and long-term neurological condition when accounting for years lost due to disability. The review aimed to discuss what possible mechanisms are behind a largely unknown evolutive process.

Genetic factors may determine how susceptible a person is to a migraine attack while environmental factors may trigger an attack, according to the review. Genome-wide association studies, which test for differences in allele frequencies of single nucleotide polymorphisms over the genome in migraine patients and controls, found that multigenetic variants, as opposed to a single gene, can contribute to migraine susceptibility.

Epigenetics, or “modification of gene expression without altering the underlying DNA sequence” may also play a factor. However, epigenetics is a new area of research and only a handful of studies have been conducted on patients with migraine. Some studies found cortical structural changes in patients but results are unclear as to whether cortical thinning or thickening took place in the brain. Structural changes like gray matter changes may also be a cause.

Many factors can trigger a migraine attack, and stess and lack of sleep “are probably the most common triggers,” according to the review. The researchers divide migraines into a preliminary phase, a pain phase, and a postdrome phase, as migraine attacks tend to follow patterns. An aura phase will occur in around 15-20% of patients. During the postdrome phase, about 80% of patients report one non-headache symptom.

“To date, studies failed to shed any light on how such genetic alterations may be responsible for migraine pathophysiology or any evolutive mechanism” the review states. “On the other hand, anatomical changes in the brain of a migraine patient exist even from early childhood, but they do not seem to have any functional consequences.”

Migraine is an evolutive condition, even in its episodic form. According to authors, different mechanisms such as cortical excitability in the aura phase and hypothalamic alterations in the premonitory phase are involved in the evolutive process of the attack.

“The causality dilemma of whether such changes are responsible for how migraine evolves, or whether migraine mechanisms drive these anatomic changes, remains to be answered” the review states.

Reference

Andreou AP, Edvinsson L. Mechanisms of migraine as a chronic evolutive condition [published online December 23, 2019]. J Headache Pain. doi: 10.1186/s10194-019-1066-0.