Abstract Objective: The KCNQ2 gene mutations (KCNQ2), a known cause of neuronal potassium channel dysfunction in brain cells, causes susceptibility to seizures beginning within the first days of life. Seizure semiology, severity and cognitive sequela can vary depending on the type of KCNQ2 mutation. Cognitive impact ranges from moderate to severe; no known consistent presentation. KCNQ2 affects approximately 2.8 in 100,000 births: over 3,000 annual cases worldwide. We describe the neuropsychological findings of an 11-year-old female with a monoallelic mutation of the KCNQ2 gene, and history of seizures. EEG indicated generalized epilepsy syndrome with a right occipital focal area of dysfunction. We highlight the importance of neuropsychological evaluation in medical and psychological management of children with KCNQ2. Methods: Medical history includes multifocal seizures beginning at 2 days old and significant anxiety, both managed with medication, language delay, and a diagnosis of KCNQ2 at age 9. A comprehensive neuropsychological evaluation was conducted to assess slower processing speed, behavioral concerns, and anxiety. Results: Evaluation revealed low average overall cognition and average academic performances, with strengths in verbal comprehension, fluid reasoning, and written expression. Cognitive processing speed was atypical, with slow processing speed affecting her performance across multiple domains. Behavior assessment supports Generalized Anxiety Disorder. Conclusion: This case of a girl with KCNQ2 demonstrated an atypical cognitive and behavioral profile, contributing to our limited knowledge of how KCNQ2 presents. The patterns of her performances add to the literature of the KCNQ2 gene mutation and raise important questions regarding the role of KCNQ2 in manifestations of cognitive and behavioral symptoms.