Mutations in the sodium channel gene SCN2A cause neonatal epilepsy with late-onset episodic ataxia
Original research article by N. Schwarz et al. (2016).
Read the abstract here.
All four individuals experienced their first seizure before they were one month old. Three individuals were considered “seizure-free” before their first birthday. The fourth individual was considered seizure-free at the age of 13 months; however, he did experience isolated seizures at ages 3, 6, and 14. While the individuals were reported to be seizure-free, all four presented with episodes of ataxia (coordination issues) and three of the four individuals experienced headaches, slurred speech, and balance issues. The frequency and duration of these episodes varied between individuals. Some of the researchers’ observations are further summarized below.Linked with signaling in the brain, genetic changes (mutations) in the SCN2A gene have been associated with various degrees of epilepsy, including neonatal-infantile seizures. In this research study, Schwarz and colleagues describe four cases of individuals with mutations in the SCN2A gene. These individuals experienced seizures early in their lives as well as other episodic symptoms that began later in childhood. These “episodes” occurred sporadically, with each individual having periods where they experienced no symptoms alternating with periods where the symptoms presented. Episodic symptoms varied in frequency and severity between the four individuals (see the table below for additional information). One case had been previously identified by the researchers, but the other three cases were newly identified via clinical observations and subsequent genetic testing.