Abstracts

Ring chromosome 20 syndrome is characterized by refractory epilepsy, cognitive impairment, behavioural problems, and sometimes dysmorphic features. Most cases have been sporadic. Clinical characteristics of epileptic seizures, neurocognitive assessment, EEG data and cytogenetic studies in 3 family members, mother and 2 children, are reviewed. The mother experienced first epileptic seizures at 23 years as a single generalized tonic-clonic seizure. Seizure control was obtained by combining VPA and LTG. Her cognitive level is normal and she has full working capacity. The daughter is now 18 years old and experienced first seizures at 7 years. From the beginning she had 100-200 seizures per month with clinical picture of complex partial seizures. Nonconvulsive status epilepticus was verified by videoEEG. After many drug trials she is on VPA and LTG with satisfactory seizure control. She had normal cognitive level from the beginning but has increasing learning disabilities and cognitive testing at 16 years showed subnormal intelligence. The son, aged 16 years had examined for jerking during infancy. He exhibited first epileptic seizures at 5 years. He has had prolonged complex partial seizures with frontal and temporal features verified by videoEEG. Seizure control has been poor with 9 AEDs and different combinations. VNS has been implanted for 1 year ago with unsatisfied seizure control. He had attentional, behavioural and learning difficulties since preschool age. His cognitive level corresponds with subnormal intelligence. No dysmophic features were discovered. The cytogenetic analysis on peripheral leukocytes by standard methods revealed ring 20 chromosomal mosaicism in the affected siblings. Only a few cells with a 20 ring chromosome were found in the mother. A chromosome abnormality can be identified underlying familial epilepsy. In this family with ring chmosome 20 mosacism epilepsy and cognitive problems exacerbated in successive generations.