Genetic Factors in Spike‐wave Absences

Abstract

SUMMARY The object of the study presented here was to obtain information about the genetics of absence epilepsies from the family histories of the patients and EEG examination of their siblings. There were 239 patients with absence epilepsy, and EEGs were recorded of 242 siblings of 109 patients, and of 685 control children. In 30% of the families, at least one relative had a history of seizures. The highest incidence, 7 % and 6 %, was in siblings and parents. The incidence of seizures was higher in the families of female than of male probands. The EEGs of 242 siblings showed theta rhythms, spike‐wave patterns or photosensitivity in 28 %. Of the siblings 1–8 yr old, 19 % had theta rhythms with maximum incidence, 27 %, in children 3–4 yr old. This was significantly more frequent than in control children. Spike‐waves were elicited by photic stimulation in 12% of the siblings, the maximum in children 11–12 yr old, 27%. Spike‐waves at rest and during hyperventilation were found in up to 20% of the siblings, depending on age. The maximum incidence in controls did not exceed 3 %. Occipital delta rhythms showed a different age distribution in siblings and controls with a maximum at 9–10 yr in siblings and at 3–4 yr in controls. The overall incidence of occipital delta rhythms was about the same in siblings and controls. The relations of the various EEG traits with each other were analyzed. Theta rhythms, spike‐waves evoked by photic stimulation, and spike‐waves at rest and during hyperventilation occurred in the siblings independently of each other. Occipital delta activity and photosensitivity were inversely related in that siblings of patients with delta rhythms were less often photosensitive than siblings of patients without delta activity. In accordance with former studies occipital delta rhythms are interpreted as a symptom of a partially genetically determined inhibitory cerebral function. The relations of EEG findings in siblings and clinical data of the probands were examined. The only positive relation was that the siblings of patients with myoclonicastatic seizures had a statistically significant higher incidence of photosensitivity. Taken as a whole, the results suggest that epilepsies with spike‐wave absences are not inherited by an autosomal dominant gene, but that several genetic factors are responsible, some mutually independent and some either reinforcing or inhibiting the others. RÉSUMÉ Le but de cette étude était ďobtenir des informations sur la génétique des absences épileptiques, à partir des histoires familiales des patients et de ľEEG de leurs frères et soeurs. II y avait 239 patients avec des absences épileptiques et ľon a pratiqué un EEG chez 242 frères et soeurs de 109 patients. Dans 30% des families, un des membres de celle‐ci présentait une histoire de crises. Le pourcentage le plus élevé, 7% et 6%, se trouve chez les frères et soeurs et leurs parents. Ľincidence ďune histoire familiale positive était plus élevée pour les propositus de sexe féminin que pour ceux de sexe masculin. Les EEG des 2...

Allelic association of juvenile absence epilepsy with a GluR5 kainate receptor gene (GRIK1) polymorphism

“…The familial clustering of JAE with childhood absence epilepsy, juvenile myoclonic epilepsy, and epilepsy with GTCS on awakening suggests a shared genetic predisposition of this IGE spectrum [Berkovic et al, 1987;Beck-Mannagetta and Janz, 1991;Janz et al, 1992Janz et al, , 1994Reutens and Berkovic, 1995]. However, the familial segregation of JAErelated phenotypes does not follow simple Mendelian inheritance [Berkovic et al, 1987;Greenberg et al, 1992;Jimenez et al, 1996], even when the common IGE-associated generalized spike-wave discharges in the electroencephalogram (GSW-EEG) of clinically healthy family members are considered as subclinical trait markers [Metrakos and Metrakos, 1961;Doose et al, 1973;Pedley, 1991].…”

Genes and epilepsy.

“…These include 'grand mal' epilepsy, 'absence' epilepsy, juvenile myoclonic epilepsy of Janz, benign rolandic epilepsy with centrotemporal spikes, and febrile convulsions. In addition, a genetic contribution to the aetiology of several EEG patterns, including generalised spike waves, focal spikes, and the photoconvulsive response, has been identified.6 7 Most commonly, the conclusion has been that the mechanism of inheritance is 'multifactorial', although not Lastly, the mitochondrial genome can be regarded as a collection of candidate epilepsy genes. It is not difficult to envisage how disruption of cellular energy metabolism may initiate seizure activity, and myoclonic seizures are a component of the phenotype in several diseases in which abnormalities of the mitochondrial genome have been documented.…”

Epilepsy In Nigeria – A Review Of Etiology, Epidemiology And Management

“…These include several well-defined syndromes such as juvenile myoclonic epilepsy (JME), absence epilepsy and benign childhood epilepsy with centrotemporal spikes. Many of the recessively inherited disorders of lipid and aminoacid metabolism may be associated with seizures 31,32 Although there is a high incidence of parasitic infections in Nigeria, there is little evidence that these parasites commonly cause epilepsy locally 36 . There are however, many reports from other parts of the world, especially other developing countries, incriminating parasites in the causation of epilepsy 39 .…”