A large proportion of children with migraine have a family history of migraine. Furthermore, children who have headaches associated with acute illnesses are more likely to have a family history of migraine (Kandt and Levine 1987). However, even though 72% to 89% of migrainous children have a positive family history, the relative contributions of genetics or other factors generally remain unclear. One estimate suggests 52% heritability (Ziegler et al 1998). But for specific types of migraine, the role of genetics is more certain; a gene for the autosomal dominantly inherited, familial hemiplegic migraine 1 (a subtype of migraine with aura) is due to a defect in a calcium-channel gene in up to 75% of cases. Surprisingly, familial hemiplegic migraine is 1 of 3 allelic disorders (ie, different alleles of the same gene) due to defects in calcium channel alpha 1A subunit gene (CACNA1A) on chromosome 19p13 the others being episodic ataxia type 2 and chronic spinocerebellar ataxia type 6. In other families with familial hemiplegic migraine 2, the chromosome 1q23 gene for sodium-potassium ATPase pump is associated with familial hemiplegic migraine, benign familial infantile convulsions, permanent mental retardation, and a family history of confusional migraine (Vanmolkot et al 2006). With the variability or lack of inheritance patterns that characterize variants of migraine, it is likely that ophthalmoplegic migraine and perhaps other variants are not really migraine (Kandt and Goldstein 1985), a concept that is now recognized by the International Headache Society (Headache Classification Subcommittee of the International Headache Society 2004).