TY - JOUR
T1 - Amitriptyline use in individuals with KCNQ2/3 gain-of-function variants
T2 - A retrospective cohort study
AU - De Wachter, Matthias
AU - Millevert, Charissa
AU - Nicolai, Joost
AU - Cats, Elisabeth
AU - Kluger, Gerhard
AU - Milh, Mathieu
AU - Cloarec, Robin
AU - Syrbe, Steffen
AU - Arts, Katrijn
AU - Jansen, Katrien
AU - Krygier, Magdalena
AU - Smigiel, Robert
AU - Auvin, Stephane
AU - Olofson, Kern
AU - Gjerulfsen, Cathrine Elisabeth
AU - Ceulemans, Berten
AU - Moller, Rikke S.
AU - Bayat, Allan
AU - Weckhuysen, Sarah
PY - 2025
Y1 - 2025
N2 - ObjectiveHeterozygous gain-of-function (GOF) variants in KCNQ2 and KCNQ3, encoding the voltage-gated potassium channel subunits Kv7.2 and Kv7.3, lead to neurodevelopmental disorders for which no established treatments are available. Amitriptyline, an antidepressant, blocks Kv7.2/Kv7.3 and has previously been reported to be effective in a single individual with a KCNQ2 GOF variant. We designed a retrospective, single-arm, multicenter study to investigate the effects of amitriptyline in a real-world setting.MethodsWe used a 7-point Likert scale to measure seizure frequency, clinical examination, motor function, alertness, skill acquisition, communication, mood, behavior, self-care, sleep, tiredness, and electroencephalogram at baseline, after a minimum of 6 weeks of intervention, and, if applicable, after discontinuation. Adverse events were assessed in all participants, and the effectiveness of the treatment was evaluated in 11 individuals who received a minimum dosage of .5 mg/kg/day for at least 6 weeks. Data were collected from October 2023 to August 2024.ResultsThirteen individuals, eight with a pathogenic KCNQ2 GOF variant and five with a pathogenic KCNQ3 GOF variant, were included. Nine were female, and the median age at start of amitriptyline was 7.1 years (range = 1.5-20 years). Eleven individuals received a minimum dosage of .5 mg/kg/day for at least 6 weeks. The median dosage of amitriptyline administered was 1 mg/kg/day, with a median treatment duration of 29 weeks. Although amitriptyline was ineffective in two individuals (18%), eight (72%) demonstrated at least minimal improvement in two or more domains, with improvements in alertness and communication being the most frequently reported. In those with reported improvements, amitriptyline was discontinued in four individuals, but continued improvements were seen, to the same or greater extent compared to treatment. The remaining five individuals are on continued treatment because of perceived benefits.SignificanceOverall, the effect of amitriptyline remains unclear, and formal n-of-1 trials are needed to investigate the precise effects of amitriptyline in KCNQ GOF-related neurodevelopmental disorders.
AB - ObjectiveHeterozygous gain-of-function (GOF) variants in KCNQ2 and KCNQ3, encoding the voltage-gated potassium channel subunits Kv7.2 and Kv7.3, lead to neurodevelopmental disorders for which no established treatments are available. Amitriptyline, an antidepressant, blocks Kv7.2/Kv7.3 and has previously been reported to be effective in a single individual with a KCNQ2 GOF variant. We designed a retrospective, single-arm, multicenter study to investigate the effects of amitriptyline in a real-world setting.MethodsWe used a 7-point Likert scale to measure seizure frequency, clinical examination, motor function, alertness, skill acquisition, communication, mood, behavior, self-care, sleep, tiredness, and electroencephalogram at baseline, after a minimum of 6 weeks of intervention, and, if applicable, after discontinuation. Adverse events were assessed in all participants, and the effectiveness of the treatment was evaluated in 11 individuals who received a minimum dosage of .5 mg/kg/day for at least 6 weeks. Data were collected from October 2023 to August 2024.ResultsThirteen individuals, eight with a pathogenic KCNQ2 GOF variant and five with a pathogenic KCNQ3 GOF variant, were included. Nine were female, and the median age at start of amitriptyline was 7.1 years (range = 1.5-20 years). Eleven individuals received a minimum dosage of .5 mg/kg/day for at least 6 weeks. The median dosage of amitriptyline administered was 1 mg/kg/day, with a median treatment duration of 29 weeks. Although amitriptyline was ineffective in two individuals (18%), eight (72%) demonstrated at least minimal improvement in two or more domains, with improvements in alertness and communication being the most frequently reported. In those with reported improvements, amitriptyline was discontinued in four individuals, but continued improvements were seen, to the same or greater extent compared to treatment. The remaining five individuals are on continued treatment because of perceived benefits.SignificanceOverall, the effect of amitriptyline remains unclear, and formal n-of-1 trials are needed to investigate the precise effects of amitriptyline in KCNQ GOF-related neurodevelopmental disorders.
KW - <italic>KCNQ2</italic>
KW - <italic>KCNQ3</italic>
KW - neurodevelopmental delay
KW - <italic>n</italic>-of-1 trial
KW - precision medicine
KW - PLACEBO
KW - ENCEPHALOPATHY
KW - STRATEGIES
KW - TRIAL
U2 - 10.1111/epi.18310
DO - 10.1111/epi.18310
M3 - Article
SN - 0013-9580
JO - Epilepsia
JF - Epilepsia
ER -