A distinctive seizure type in patients with CDKL5 mutations: Hypermotor-tonic-spasms sequence

Recent recognition of the encephalopathy associated with CDKL5 (cyclin-dependent kinase-like 5) mutations has led to molecular diagnosis in affected girls. A characteristic progressive 3 stage electroclinical epilepsy course occurs with onset by 3 months of age.1,2 After we observed unusual prolonged seizures in a girl with CDKL5 mutations, we sought to determine if CDKL5 mutations were associated with a distinctive electroclinical seizure type. ### Methods. We reviewed the video-EEG monitoring (VEM) and clinical details of all girls with CDKL5 abnormalities recruited into our epilepsy genetics research studies. Details of the molecular methods are described elsewhere.2 In one subject a deletion of CDKL5 was revealed by an Agilent aCGH 44K array and confirmed by quantitative PCR. #### Standard protocol approvals, registrations, and patient consents. The study was approved by the Human Research Ethics Committee of all participating institutions. Signed informed consent for study participation and publication of the videos was obtained from the participants' parents. ### Results. Four of 5 girls with CDKL5 mutations had the distinctive seizure type. The clinical and molecular details are reported (table e-1 on the Neurology ® Web site at www.neurology.org, molecular data previously reported for patients 1, 3, and 43). Table 1 describes the electroclinical features of the seizure type captured during VEM …