Abstracts

Recently, we described a large group of families segregating a distinct type of temporal lobe epilepsy with familial recurrence (FMTLE). Initial pedigree analysis pointed to a strong genetic predisposition for the development of hippocampal atrophy in these families. The objective of this study was to determine the type of inheritance that can most appropriately explain the recurrence of the disease in these families. Complex segregation analysis was performed using the software POINTER[copy]. We used a series of 98 nuclear families, derived from 29 unrelated pedigrees. A total of 602 family members, including 147 patients were studied. Parameters estimated were: dominance (d), displacement (t), allelic frequency (q), multifactorial heritability (H). Different models were compared by likelihood coefficient tests. We rejected the absence of genetic effect ( [chi][sup2] = 59,480; p = 0,000), absence of a main gene ( [chi][sup2] = 59,480; p = 0,000), autosomal recessive inheritance ( [chi][sup2] =17,766; p = 0,000) and co-dominant model ( [chi][sup2] = 7,050; p = 0,029). However, we could not reject the absence of multifactorial inheritance ( [chi][sup2] = 0,010; p = 0,920) and autosomal dominant inheritance ( [chi][sup2] = 0,027; p= 0,987). To our knowledge this is the first segregation studied performed in FMTLE. Our results strength the evidence for genetic predisposition in this disorder. In addition our data provides additional evidence for the presence of a major gene, which could be involved in the development of hipocampal atrophy in these patients. Linkage studies are under way in order to identify the major gene involved in FMTLE. (Supported by FAPESP)