Familial Temporal Lobe Epilepsy with Hippocampal Atrophy Is Not Linked to Chromosome 10q.
Abstract number :
1.263
Submission category :
Year :
2000
Submission ID :
2923
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Eliane Kobayashi, Fernando Cendes, Solange C Sousa, Carlos Am Guerreiro, Marilisa M Guerreiro, Iscia Lopes-Cendes, UNICAMP, Campinas, Brazil.
RATIONALE: At least two different types of familial temporal lobe epilepsy (TLE) have been described: familial lateral TLE with auditory symptoms and familial TLE with ictal semiology of mesial temporal onset (FMTLE). A locus for familial lateral TLE has been mapped on chromosome (ch) 10q. OBJECTIVES: To describe the MRI and clinical findings in a large series of FMTLE and to investigate whether these families show linkage to ch 10q. METHODS: We obtained detailed pedigrees and interviewed most of the possibly affected subjects. All probands and whenever possible other affected family members underwent MRI investigations. For the linkage studies we genotyped 14 of the identified families, a total of 143 individuals with 73 affecteds. We used 4 markers: D10S185, D10S574, D10S577 and D10S192, which flank the 15 cM candidate interval on ch 10q. Two-point lod scores were calculated for all families combined. We assumed an autosomal dominant inheritance with 0.75 penetrance. RESULTS: To date, we have identified 22 unrelated families with FMTLE, MRI was performed in 84 patients, and showed hippocampal atrophy (HA) in 45 (53%). EEG and clinical findings indicated mesial temporal epileptogenic focus. Twenty-two % of patients had seizure remission, 54% had good seizure control with medication and 24% had poor seizure control. We found negative lod scores for all 4 markers tested. The lod scores were significantly negative (<-2.00) up to theta=0.05 for D10S185, theta=0.10 for D10S574, theta=0.25 for D10S577 and theta=0.15 for D10S192. CONCLUSIONS: We found HA in 53% of patients, including those with benign course or seizure remission. These results indicate that genetic factors may play an important role in the development of hippocampal pathology in FMTLE and that HA is not necessarily related with a poor seizure outcome. In addition, we significantly excluded linkage between FMTLE and the candidate locus on ch 10q. This is further evidence of heterogeneity among the different types of familial TLE. Study supported by FAPESP - SP