Sporadic hemiplegic migraine and epilepsy associated with CACNA1A gene mutation.

Familial hemiplegic migraine (FHM) is a clinically and genetically heterogeneous disease most commonly linked to CACNA1A gene mutation. Epilepsy rarely occurs in FHM and is seen predominantly with specific CACNA1A gene mutations. Here we report a sporadic case of FHM1 linked to S218L CACNA1A gene mutation with the triad of prolonged hemiplegic migraine, cerebellar symptoms, and epileptic seizures. Epilepsy in this syndrome follows the pattern of isolated unprovoked seizures occurring only during childhood and hemiplegic migraine-provoked seizures occurring during adulthood. Clinical and electrographic status epilepticus can occur during prolonged migraine attacks. We suggest that patients with seizures, ataxia, and hemiplegic migraine be genetically tested for FHM. Patients with prolonged hemiplegic migraine attacks and confusion should be tested with continuous EEG recording to ascertain whether electrographic status is occurring, as intensive antiepileptic treatment not only resolves status but immediately stops hemiplegic migraine and improves associated neurological deficits.