Parietal epilepsy with evoked and spontaneous spikes: report on siblings with possible genetic transmission.
The group of benign infantile epilepsies "with evoked spikes" is not unusually genetically transmitted. Only 2 out of 31 cases of parietal epilepsy "with evoked spikes" are siblings. In this study, we present the clinical and EEG characteristics of a brother and sister who suffer from this rare form of epilepsy, and those of their younger sister, not epileptic, who shows "podalic" evoked spikes. An older sister has spontaneous spikes but no seizures. These phenomena are not found in their parents. The two siblings show a very similar clinical and EEG evolution; in fact, both suffered initially from parietal epilepsy "with evoked spikes" and, after two years of this form, they developed temporo-central (or rolandic) epilepsy "with evoked spikes" that still persists. Their intellectual development is normal, but their scholastic performance is rather poor. The youngest sister, who presents only evoked "podalic" spikes, has a normal intellectual development. One of the most accepted hypotheses as to the nature of evoked spikes is that in a particular period of childhood an area of cortical functional deafferentation occurs, which disappears with further maturation of the central nervous system.