Temporal lobe abnormalities on brain MRI in healthy volunteers: a prospective case-control study. Reply

We thank Striano et al. for their interest. As we stated, all our patients had a very mild epileptic disorder with good long-term prognosis. Regarding affected relatives, we found that the most common epileptic phenotype was benign temporal lobe epilepsy (bTLE) and a detailed family history led to the discovery of a family with autosomal dominant bTLE. Nevertheless, other epileptic disorders were also found in the first degree relatives of the patients. Genetic predisposition is an important causal factor of bTLE, even though familial TLE inherited in an autosomal dominant manner is rare. This is not surprising because TLE is primarily heterogeneous with complex genetics where putative susceptibility genes and environmental factors coordinate to produce the disease phenotype. In addition, about 18% of our patients with bTLE experienced simple febrile seizures but not other precipitating cerebral insults including complex febrile seizures. Spontaneous seizures started in adulthood or later. When analyzing a series of variables that might predict a good prognosis of TLE, we found that only older age at onset (usually 20 years) predicted good seizure outcome and greater remission rates in patients with sporadic bTLE. This occurred despite complex partial or secondary generalized seizures, focal EEG abnormalities, or signs of HS on brain MRI. Radiologic evidence of HS was seen in about 40% of patients with longstanding bTLE and drug-sensitive epilepsy, indicating that HS is not necessarily related to seizure severity. In addition, genetic and environmental factors may affect the causation and severity of TLE.