Familial temporal lobe epilepsy|Epilessia temporale familiare

We review the clinical, neurophysiological and genetic features of Familial Temporal Lobe Epilepsy (FTE). This condition may be distinguished Into 2 variants mesial and lateral, on the basis of the ictal symptoms. The mesial variant has an autosomal dominant inheritance; it includes a subgroup with adult onset, mild focal seizures and benign evolution and a subgroup with earlier onset, variable evolution and mesial temporal sclerosis. The lateral variant is transmitted with an autosomal dominant trait; it shows a variable age of onset, seizures with typical auditory auras, good response to treatment and mild and inconstant temporal EEG abnormalities. While no linkage has been established so far in mesial FTE, a gene (LGI1) whose mutations cause lateral FTE in at least a subset of families has been recently identified. The predicted protein structure of LGI1 consists, in the N-terminal portion, of three leucine-rich repeats (LRRs) flanked with typical cysteine-rich repeat sequences and, in the C-terminal portion, of seven newly identified repeats of about 50 aminoacids. LRRs are widespread among different classes of the extra- and intra-cellular proteins and often mediate interactions to other proteins, contributing to the mechanisms of axon guidance and synaptogenesis.