Familial vasovagal syncope associated with migraine.

Syncope affects all age groups and is characterized by a brief sudden loss of consciousness followed by fast recovery. Vasovagal syncope, the most common type, is generally assumed to be due to venous pooling and an abnormal sympathetic response. In approximately 20% of cases, more than one family member is affected. Vasovagal syncope has been documented in a high proportion of patients with migraine. Three generations of a family with comorbid vasovagal syncope and migraine are described. Data were collected from the medical files (index patient and eight siblings) and interviews with the patient's mother. Information was available for 21 family members. Eleven of the 14 family members with a diagnosis of migraine (78%) also had vasovagal syncope, and 11 of the 12 family members with vasovagal syncope (92%) also had migraine. Age at first episode of syncope ranged from 2 to 7 years; age at first migraine headache was less than 10 years in most cases. The high incidence rates combined with the lack of gender predominance may point to a possible common pathophysiology of the two disorders and, perhaps, an autosomal dominant mode of inheritance. Further investigations are needed to corroborate a genetic link.