HLA antigens and idiopathic epilepsy.

Fifty-two mentally normal Egyptian children with idiopathic epilepsy were human leukocyte antigen (HLA) typed. They were divided into two subgroups: generalized tonic-clonic seizures (36 cases) and absences (16 cases). When the frequencies of HLA antigens were compared statistically with those of 120 normal controls, HLA-A9 was found to be significantly higher in the total epilepsy group and the two subgroups. This finding, together with the low HLA-A9 gene frequency in our group of normal Egyptians as compared with other ethnic populations, strongly suggests an association between antigen A9 and one or more of the polygenes controlling the development of idiopathic epilepsy. The relative risk indicated that persons having antigen A9 are 16 times more susceptible to epilepsy than persons lacking it.