Epilepsy in ring 14 syndrome: a clinical and EEG study of 22 patients

Summary Purpose To characterize epileptic phenotype, electroencephalography (EEG) features, and epileptic evolution in patients with ring 14 r(14) syndrome. Methods Twenty-two patients with ring chromosome 14 were enrolled in the study. We examined age at onset, seizure semiology and frequency at onset and at follow-up, drug responsiveness/resistance, and interictal/ictal EEG data. The degree of severity of the epileptic phenotype negatively influences child cognitive development. Key Findings The incidence of epilepsy in patients with r(14) syndrome is virtually 100%, characterized by early onset, polymorphic seizures, and drug-resistant seizures. In addition, we ascertained focal secondarily generalized epilepsy, seizure cluster tendency, frequent status epilepticus, and a rather typical epilepsy evolution. EEG abnormalities consisted of slow background activity with pseudoperiodic bursts of generalized slow waves in the early stage, focal frontotemporal or temporoposterior slow waves with multifocal spikes interposed, and unusual rhythmic fast recruiting posterior spikes followed by secondary generalization. The degree of severity of the epileptic phenotype negatively influences child cognitive development. Significance This study provides a more precise definition of seizure types, natural history, and drug responsiveness of r(14) syndrome, a highly epileptogenic chromosomal condition.