Effecting a differential diagnosis between basilar migraine and hemiplegic migraine is difficult. Familial hemiplegic migraine is a form of hemiplegic migraine headache that runs in families. Some mutations in NBCe1 have been associated with Familial hemiplegic migraine. The ICHD classification and diagnosis of migraine distinguish 6 subtypes of hemiplegic migraine. Central Facial palsy occurs in patients who are hemiplegic. There are also non-familial cases of hemiplegic migraine, termed sporadic hemiplegic migraine. It is especially informative to show migrational defects in hemiplegic cerebral palsy associated with seizures. Also, nonfamilial cases of hemiplegic migraine are seen, termed sporadic hemiplegic migraine. Familial hemiplegic migraine (FHM) has been linked to mutations in the calcium channel gene. Four genes have been shown to be involved in familial hemiplegic migraine. Still others present with symptoms common to both SCA6 and familial hemiplegic migraine. An association with some forms of familial hemiplegic migraine (FHM) has also been found. There is some evidence to support its use to prevent hemiplegic migraine.