Genetic and environmental factors in febrile seizures: a Danish population-based twin study.
ABSTRACT The relative importance of genetic and environmental factors in the etiology of febrile seizures was estimated using a large, unselected population-based twin sample. A total of 34,076 twins (aged 12-41 years), recruited from the Danish Twin Registry, were screened for febrile seizures by questionnaire. Information was obtained from 11,872 complete pairs. Concordance rates, odds ratios and correlations were used to assess the degree of similarity in monozygotic (MZ) and dizygotic (DZ) twins. Model fitting and estimation of heritability (proportion of the population variance attributable to genetic variation) were performed using standard biometrical methods. Significantly higher probandwise concordance rates were found for MZ compared with DZ twins (0.36 and 0.12, P < 0.01). Odds ratios and correlations showed a similar pattern. An etiological model including additive genetic effects and individual-specific environmental factors provided the best fit to the data with a heritability for febrile seizures of 70% (95% CI: 61-77%). The remaining 30% of the variation could be attributed to individual-specific environmental factors. In conclusion, this study has confirmed a major impact of genetic factors in the etiology of febrile seizures. Future studies aimed at identifying the specific genetic factors and environmental exposures involved in determining febrile seizure risk are clearly warranted.
Article: A Dutch family with 'familial cortical tremor with epilepsy'. Clinical characteristics and exclusion of linkage to chromosome 8q23.3-q24.1.[show abstract] [hide abstract]
ABSTRACT: To describe the clinical characteristics of a large Dutch family with cortical tremor with epilepsy (FCTE) and to test for genetic linkage of FCTE to chromosome 8q23.3-q24.1. FCTE is an idiopathic generalised epilepsy of adult onset with autosomal dominant inheritance. It is characterised by kinesiogenic tremor and myoclonus of the limbs, generalised seizures, and electrophysiological findings consistent with cortical reflex myoclonus. Genetic analysis has been performed in five Japanese families. In all families, linkage was shown to chromosome 8q23.3-q24.1. Clinical and electrophysiological data of a four-generation family, suspected of autosomal dominant inherited FCTE, were collected and linkage analysis was performed. Results Clinical and electrophysiological findings were consistent with a diagnosis of FCTE. Of 41 relatives examined, 13 subjects were considered to be definitely affected, three were probably affected and ten were unaffected. In 15 relatives, the diagnosis could not be established. Linkage to chromosome 8q23.3-q24.1 was excluded. In this family with autosomal dominant FCTE, specific clinical and electrophysiological features were identified. Exclusion of linkage to chromosome 8q23.3-q24.1 indicates that genetic heterogeneity exists for FCTE.Journal of Neurology 08/2002; 249(7):829-34. · 3.47 Impact Factor