DO GENETIC EFFECTS INFLUENCE THE FACTORS THAT PRECIPITATE SEIZURES?
Abstract number :
1.199
Submission category :
Year :
2003
Submission ID :
2207
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Marit H. Solaas, Marianne J. Kjeldsen, Mogens L. Friis, Karl O. Nakken, Grethe B. Refsland, Jack M. Pellock, Linda A. Corey Institute of Medical Genetics, University of Oslo, Oslo, Norway, Norway; Department of Neurology, Odense University Hospital, Odens
In this study we wanted to examine the factors that provoke seizures in a sample of twins who were concordant for epilepsy in order to determine if genetic effects have an impact upon seizure precipitating factors.
Study participants were originally ascertained through twins who responded positively to queries regarding a history of seizures contained in a survey questionnaire sent to twins included in twin registries in the US, Denmark and Norway. Twins who indicated a history of seizures have been evaluated and their seizure and epilepsy types classified according to the ILAE. Twin zygosity was determined by DNA markers. The twins were asked about the presence of 36 factors known to provoke seizures. A twin pair was considered concordant for epilepsy regardless of seizure and epilepsy subtypes, and concordant for provoking factors if pair members shared at least one of these factors. Classical probandwise concordance rates were computed to compare similarity between monozygotic (MZ) and dizygotic (DZ) twins within and across twin samples for seizure precipitating factors.
To date, members of 1019 twin pairs from the three population-based twin samples have been tested for zygosity and classified according to the ILAE. Among these twin pairs 87 MZ pairs and 40 DZ pairs were concordant for seizures, although some of the pairs were discordant for seizure and epilepsy subtypes. After excluding pairs concordant for febrile seizures, 45 MZ and 28 DZ pairs were found to be concordant for epilepsy. Among these twin pairs, the concordance rates for provoking factors were 0.80 for MZ pairs and 0.33 for DZ pairs.
The results of this study suggest that genetic factors may contribute to the causes that provoke seizures. The extent to which the similarity found in the factors that provoke seizures in twin pairs concordant for epilepsy reflects concordance for specific epilepsy syndromes is not clear. We have initiated studies to further examine the degree to which provoking factors are characteristic for specific epilepsy syndromes.
[Supported by: NIH NINDS grant (NS-31564).]