An Online Survey of Caregivers of Patients with KCNQ2 Developmental & Epileptic Encephalopathy (KCNQ2-DEE)

Objective: We conducted an online survey to understand the clinical presentation of KCNQ2 developmental and epileptic encephalopathy (KCNQ2-DEE). Background: KCNQ2-DEE is an ultra-rare disorder caused by variants in the KCNQ2 gene, encoding the Kv7.2 potassium channel. KCNQ2-DEE is characterized by focal tonic seizures and severe developmental delay, which persists even when seizures are controlled. The lack of a clear understanding of the natural history of this disease makes this work of critical importance. Design/Methods: A 28-question online survey was developed to obtain de-identified data from caregivers of children with KCNQ2-DEE. It investigated demographics, seizure onset and frequency, anti-seizure medication (ASM) use, and confidence in seizure identification. Results: Seventy-one caregivers completed the survey through all of the seizure and treatment questions. Answers from cases of reported gain-of-function variants or phenotypes inconsistent with KCNQ2-DEE were excluded. Seizure onset was reported within the first 2 days of life for 90% of patients, and within the first 5 days of life for the remaining 10% of patients. At seizure onset, >50% of patients experienced >10 seizures per day; most common ASMs were phenobarbital and levetiracetam. The majority of respondents were at least 4 years of age. The current seizure frequency range from several per day to seizure freedom in 55% of the patients. The most frequent currently used ASMs were carbamazepine and oxcarbazepine. Around three quarters of caregivers reported they had received training in seizure recognition by the neurology team based on video electroencephalography, and were highly confident in identifying seizure occurrence. Conclusions: KCNQ2-DEE imposes a significant seizure burden at disease onset. There is a significant unmet medical need that requires better treatment options. Parents/caregivers are confident in recognizing seizures and most have been trained by medical personnel using video electroencephalography-documented seizures. Disclosure: Dr. Harden has nothing to disclose. Dr. Butterfield has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals, Inc. Dr. Grayson has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals Inc. Dr. Luzon has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals, Inc.. Dr. Pimstone has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals, Inc.. Dr. Pimstone has received compensation for serving on the Board of Directors of Xenon Pharmaceuticals, Inc.. Dr. Aycardi has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals Inc. Dr. Aycardi holds stock and/or stock options in Xenon Pharmaceuticals Inc.Dr. Millichap has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Xenon Pharmaceuticals, Inc..