Interviews were obtained with members of the families of 669 epileptic subjects with 3,361 close relatives, and 470 control patients with 2,858 close relatives. A small but significant familial aggregation of idiopathic major motor epilepsy was demonstrated. This aggregation appeared to vary with the age of the proband at onset of epilepsy and was highest when the proband's epilepsy started between the ages of 0 and 31/2 years and between 91/2 and 151/2 years. No familial aggregation could be demonstrated when the age at onset was over 151/2 years, or in other types of epilepsy. Simple febrile convulsions were not included in the study. Hereditary transmission of epilepsy could not be demonstrated, but it could not be ruled out. Familial aggregation of idiopathic major motor epilepsy may be due to familial aggregation of perinatal brain injury, to inheritance, or to a combination of these factors. Further studies are needed to clarify this. Risk tables are presented, showing the chances of relatives of patients with idiopathic major motor epilepsy of developing epilepsy. The highest risk was found to occur in the close relatives of probands who had developed major motor epilepsy before 31/2 years of age: 7.6 per cent of these relatives may be expected to develop major motor seizures by 191/2 years of age, and 9.4 per cent by 391/2 years of age. Comparable control risks were 1.4 and 2.3 per cent.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health