Family history of seizures in posttraumatic and alcohol-associated seizure disorders

The potential role of genetic factors in the etiology of posttraumatic and alcohol-associated seizures was studied in 289 male patients with recurrent seizures and in 174 individuals who had never experienced a seizure. The incidence of seizures in first-degree relatives of probands was compared with that in relatives of unaffected individuals. Relatives of patients with alcohol-associated seizures had a rate ratio of 2.45 [95% confidence interval (CI) 1.41-4.25], whereas no excess incidence was noted among relatives of posttraumatic epilepsy patients (rate ratio 1.20, 0.64-2.25 CI). Relatives of probands with both antecedents showed an intermediate rate ratio of 1.72 (0.92-3.20 CI). Among probands with alcohol-associated seizures, the rate ratio of 2.05 for patients with alcohol-related seizures (i.e., spontaneously occurring seizures in association with chronic alcohol abuse) was slightly higher than that of 1.85 for probands with alcohol withdrawal seizures. Trauma severity had a slight impact on the incidence of affected relatives; patients with severe head injuries had a rate ratio of 0.73 and probands with milder trauma had a rate ratio of 0.99. The results indicate a limited, if any, role of genetic predisposition in development of posttraumatic seizures. Alcohol-related seizures, however, showed familial aggregation of unprovoked seizures, suggesting an involvement of genetic factors in the origin of such seizures.