RESUMEN
Many antiseizure medications cause apoptotic cell death in developing brains. The newer antiseizure medication lacosamide is increasingly used in neonates and infants. Neurotoxicity of lacosamide and its combination with levetiracetam was studied in neonatal mice. Animals received single or repeat injections of saline, phenobarbital (75mg/kg), lacosamide (20-40mg/kg), levetiracetam (100mg/kg), lacosamide (40mg/kg) + levetiracetam (100mg/kg) and euthanized at 6 to 30 hours. Cells undergoing apoptosis were increased in the brains of phenobarbital-treated animals. Densities of apoptotic profiles following lacosamide and levetiracetam treatment did not differ from saline-treated controls. Findings suggest that lacosamide, levetiracetam and their combination do not cause apoptosis in developing mouse brains. ANN NEUROL 2024.
RESUMEN
Phenotypic heterogeneity in monogenic neurodevelopmental disorders can arise from differential severity of variants underlying disease, but how distinct alleles drive variable disease presentation is not well understood. Here, we investigate missense mutations in DNA methyltransferase 3A (DNMT3A), a DNA methyltransferase associated with overgrowth, intellectual disability, and autism, to uncover molecular correlates of phenotypic heterogeneity. We generate a Dnmt3aP900L/+ mouse mimicking a mutation with mild to moderate severity and compare phenotypic and epigenomic effects with a severe R878H mutation. P900L mutants exhibit core growth and behavioral phenotypes shared across models but show subtle epigenomic changes, while R878H mutants display extensive disruptions. We identify mutation-specific dysregulated genes that may contribute to variable disease severity. Shared transcriptomic disruption identified across mutations overlaps dysregulation observed in other developmental disorder models and likely drives common phenotypes. Together, our findings define central drivers of DNMT3A disorders and illustrate how variable epigenomic disruption contributes to phenotypic heterogeneity in neurodevelopmental disease.