These mutations can make brain cells abnormally excitable, contributing to uncontrolled seizures, developmental delays, autism, movement difficulties, and gastrointestinal problems. Over two years, both experienced substantial declines in seizure frequency, developmental improvements, and few side effects. After two years, the results included:Decreases in seizure frequency: The nine-year-old patient, who previously experienced seizures almost every day, had a 26% decrease in seizure frequency. The 14-year-old patient had a 90% reduction in seizure frequency and eventually experienced periods of seizure-free days. A model for personalized genetic medicineKim-McManus cautioned that the treatments remain investigational.