Genetic study of isolated hpilepsy among Egyptians

Abstract EN

-The present study was conducted in order to reveal some genetic aspects of isolated epilepsy among a sample of 200 Egyptian patients and 920 of their family members.

The work comprised clinical assessment and EEG recordings for all patients, EEG recording for their apparently normal parents, sibs and offspring and detailed genealogical analysis of each family.

The study revealed the following results: 1-The larger proportion of cases of isolated epilepsy (78%) are genetically-determined, the remaining (22%) probably represent sporadic occurrence of the disorder.

2-Among genetically-determined cases,direci inheritance of the disorder from a similarly affected parent was apparent in (15%), affection of more than one sib in (18%) and single-case affection with positive family history of clinically- similar seizures and/or epileptogenic EEG recording was detected in (39%) of affected families.

3- First and second cousinship parental consanguinity was detected in (20.87 %) of affected families.

4- Inheritance patterns in this group included: autosomal recessive (28 %), autosomal dominant (14%),X-linked recessive (23%),and mitochondrial inheritance in (35%).

5- Transmission of genetic predisposition to inherited isolated epilepsy in families is more frequent via maternal lineage than via paternal lineage (69% versus 31%).

6- Epileptic mothers transmit the disorder to their offspring more than epileptic fathers (50% versus 17.3%).

7-Male offspring of epileptic parents are more liable than female offspring to inherit and manifest the disease (64.1% versus 35.9%).

8-Prior affection with febrile convulsions during infancy and/or childhood does not entail predisposition to isolated epilepsy in later life.

9- The clinical type of seizures and the EEG recording pattern are fairly constant among patients and apparently normal members who have epileptogenic EEG recordings within the same family.

10-ln sporadic cases of isolated epilepsy, males are affected more than females (68.1% versus 31.9 % ), first and second cousinship parental consanguinity was detected in (20.45 % ) of affected families, there was no prior history of febrile convulsions in early life, no epileptogenic EEG recording could be detected in any of their first degree family members (parents, sibs and offspring) and mean age of onset of the seizures is (26±1.7) years, which is significantly higher than the corresponding value for genetically-determined cases (17±2.3) years.

11-Relevant genetically-determined disorders were detected in ( 3.4 %) and (3.6%) of family members and relatives of patients with the genetically-determined type and the sporadic type of isolated epilepsy, respectively.

Most of these disorders are nervous system-related diseases.

The results of this study point