Abstracts

Familial Mesial Temporal Lobe Epilepsy (FMTLE) is a heterogeneous syndrome where some patients may present hippocampal atrophy and pharmacoresistant seizures. Although clinical and neuroimaging features have been well characterized in FMTLE, particularly in patients with good seizure control, there has been few information about the histopathological features of the hippocampal atrophy in this group of intractable patients. It seems plausible that genetic factors may promote changes in clinical and histological phenotypes in this subgroup of patients. In the present study we evaluate the clinical and hippocampal histological features of patients with FMTLE and patients with sporadic forms of MTLE. We studied patients with FMTLE (n=20) and sporadic MTLE (n=39) who underwent surgical treatment for refractory seizures in our University Hospital. FMTLE was defined when at least two individuals in a family had clinical diagnosis of MTLE. Hippocampi from all patients were processed for Nissl/HE and Timm[apos]s stainings. Both groups we compared regarding clinical variables and qualitative and quantitative (cell densities on hippocampal subfields and intensity of mossy fiber synaptic reorganization) histological features. There were no significant differences between groups in the following: age of surgery, gender, age of first usual epileptic seizure, history of initial precipitating injury (IPI), age of IPI, latent period, ictal and interictal video-EEG patterns, presence of hippocampal atrophy and signal changes at MRI, post-operative outcome. No differences were found in cell densities in all hippocampal CA subfields (CA1, CA2, CA3, CA4), fascia dentata, hilar polymorphic region, subiculum, prosubiculum and presubiculum. However, patients with sporadic MTLE had greater intensity of mossy fiber Timm[apos]s staining in the fascia dentata-inner molecular layer (Anova with post-hoc Tukey test, [italic]p[/italic] [lt] 0,05). Patients with intractable FMTLE present a clinical profile most histological features comparable to patients with sporadic form of MTLE. Interestingly, the intensity of mossy fiber sprouting was more pronounced in patients with the sporadic form. This findings indicate that familial cases may respond diferentially to seizure-induced plastic changes. (Supported by Brazilian research agencies FAPESP (CINAPCE grant: 04/14004-9) and CNPq, and FAEPA.)