Sporadic hemiplegic migraine is a rare form of migraine headache. Migraines typically cause intense, throbbing pain in one area of the head. Some people with migraines also experience nausea, vomiting, and sensitivity to light and sound. These recurrent headaches typically begin in childhood or adolescence and can be triggered by certain foods, emotional stress, and minor head trauma. Each headache may last from a few hours to a few days.

Mutations in the ATP1A2 and CACNA1A genes have been found to cause sporadic hemiplegic migraine. The proteins produced from these genes transport charged atoms (ions) across cell membranes. The movement of these ions is critical for normal signaling between nerve cells (neurons) in the brain and other parts of the nervous system. Signaling between neurons relies on chemicals called neurotransmitters, which are released from one neuron and taken up by neighboring neurons. Mutations in the ATP1A2 and CACNA1A genes disrupt the transport of ions in neurons, which is thought to impair the normal release and uptake of certain neurotransmitters in the brain. The resulting abnormal signaling may lead to the severe headaches and auras characteristic of sporadic hemiplegic migraine.

The worldwide prevalence of sporadic hemiplegic migraine is unknown. Studies suggest that in Denmark about 1 in 10,000 people have hemiplegic migraine and that the condition occurs equally in families with multiple affected individuals (a condition known as familial hemiplegic migraine) and in individuals with no family history of the condition (sporadic hemiplegic migraine).

Sporadic means that the condition occurs in individuals with no history of the disorder in their family. While most cases result from new (de novo) mutations that likely occur during early embryonic development, some affected individuals inherit the genetic change that causes the condition from an unaffected parent. (When some people with the mutation have no signs and symptoms of the disorder, the condition is said to have reduced penetrance.) Although family members of an affected individual do not have sporadic hemiplegic migraine, some experience migraine headaches without hemiparesis. A related condition, familial hemiplegic migraine, has signs and symptoms identical to those in sporadic hemiplegic migraine but occurs in multiple members of a family.

Published Date: October 01, 2017
Published By: National Institutes of Health