Abstracts

Childhood absence epilepsy (CAE) with or without grand mal accounts for 5-15% of all epilepsies. Four subsyndromes of CAE have been described by our group, as well as by other authors. One of them is CAE that persists with adolescent or adult myoclonic seizures (MS) and grand mal (GM) seizures.
We prospectively studied 17 families of European ethnic origin and 15 families of mixed European and American Indian origin recruited from 1978 to 2002 (32 probands and 99 affected non-proband family members). Families were ascertained through a proband with persisting CAE starting between 2 and 10 years old plus adolescent-onset GM and MS. Diagnosis of seizures and epileptic syndromes was based on the ILAE classifications and were validated independently by at least two epileptologists. An extended pedigree was constructed for each family and all available affected relatives were interviewed, examined and underwent EEG studies.
Twenty-two probands were females and 10 were males (2.2:1 ratio) with the age during enrollment averaging 24.2 years (range 11 to 52). Pyknoleptic absence seizures (pAS) started at 6.5 years (range 2 to 10 years). By enrollment, pAS had persisted an average 15.6 years (range 5 to 47 years). MS started between 8 to 24 years, had persisted for 2 to 30 years by enrollment. All probands had at least one GM seizure that appeared from 6 to 22 years and had been recurring for 30 years. Forty six percent of probands showed 3 Hz single spike and slow wave complexes or 3 to 5 Hz single spike wave complexes. Fifty four percent had single spike wave complexes mixed with polyspike wave complexes. Five percent showed fast polyspike and slow wave complexes as the sole EEG trait. Neuroimaging and neurological examinations remained normal during follow-up. In 82% , monotherapy with valproate achieved seizure control; the rest needed polytherapy. In 75%, another family member was affected with epilepsy. Amongst 99 non-proband family members 57 werer females vs. 42 males. There were almost as many paternal as maternal transmission. More relatives (43.6%) had absences alone or in combination with MS or GM.
CAE persisting with MS and GM seizures of adolescent-onset is a female-preponderance syndrome characterized in probands and affected family members by pyknoleptic absences and EEG patterns of both 3 Hz spike wave complexes and 3-7 Hz polyspike wave complexes. Maternal transmission was equal to paternal transmission. These results indicate a persisting CAE syndrome distinct from Remitting CAE and Classic JME.
[Supported by: NINDS Grant No. 5RO1NS042376-03]