INTRODUCTION Linkage analyses provide strong evidence of how genetic factors influence epilepsy, due to the fact that they involve the determination of the cosegregation of specific marker alleles with epilepsy within families. AIMS. Our aim was to determine whether there was some kind of propensity to develop generalised idiopathic epilepsy (GIE) in the 15q22.1-q25.1 region in an extended multigenerational family from the Paisa de Antioquia community, which is a genetic isolate located in Colombia that segregates for GIE and has a strong capacity to detect linkage.

PATIENTS AND METHODS We selected a family containing a number of individuals suffering from epilepsy who visited the Antioquia Neurological Institute. Each affected individual had to have been diagnosed by a neurologist as suffering from non-myoclonic idiopathic epilepsy or from partial idiopathic epilepsy. All patients suspected of suffering from idiopathic epilepsy were submitted to video monitoring in order to characterise seizures electroencephalographically.

RESULTS Of the 106 individuals in this family who were included in the family tree, 76 were genotyped; 15 of them suffered from generalised clonic tonic seizures and six were considered as being possibly affected. Lod score results were significantly negative for all the markers in relation to each of the models under consideration.

CONCLUSIONS The possibility of the genes that code for the a-3, a-5 and b-4 subunits of the neuronal nicotinic acetylcholine receptor (CHRNA3, CHRNA5 and CHRNB4) situated in the 15q region being responsible for the familial aggregation of GIE in this family, as has been suggested in previous studies in other families, was ruled out.

Introducción Los análisis de ligamiento proveen una poderosa evidencia de la influencia de la herencia en la epilepsia, debido a que determinan la cosegregación de alelos de marcadores específicos con la epilepsia dentro de las familias.

Objetivo Determinar si existe susceptibilidad para desarrollar epilepsia idiopática generalizada (EIG) en la región 15q22.1-q25.1 en una familia multigeneracional extendida perteneciente a la comunidad paisa de Antioquia, un aislado genético localizado en Colombia que segrega para la EIG y con un fuerte poder para detectar ligamiento.

Pacientes y métodos Se seleccionó una familia con múltiples individuos afectados de epilepsia que consultaron al Instituto Neurológico de Antioquia. El individuo afectado debía tener un diagnóstico realizado por neurólogo de epilepsia idiopática no mioclónica o de epilepsia idiopática parcial. Se realizó videomonitorización a todos los pacientes con sospecha de epilepsia idiopática con el fin de caracterizar electroencefalográficamente las crisis.

Resultados De los 106 individuos de esta familia incluidos en la genealogía, se genotipificaron 76, de cuales 15 estaban afectados con crisis tonicoclónicas generalizadas y seis se consideraron posiblemente afectados. Los resultados de lod score son significativamente negativos para todos los marcadores según cada modelo considerado.

Conclusiones Se descarta que los genes que codifican para las subunidades a-3, a-5 y b-4 del receptor neuronal nicotínico de la acetilcolina (CHRNA3, CHRNA5 y CHRNB4) localizados en la región 15q, sean los responsables de la agregación familiar de la EIG en esta familia, como lo han sugerido estudios anteriores en otras familias.