News Finding: The researchers discovered that the mutations disrupt the ion channel's function either by cutting the flow of potassium, leading to a loss of function; or by increasing potassium flow, leading to an excess gain of function.
Paper Finding: Coexpression of Pro405Leu or Ile263Thr and wild-type channel led to a significant reduction in the current amplitude in comparison to expression of wild-type channel alone (indicated by an asterisk).
News Context: The researchers discovered that the mutations disrupt the ion channel's function either by cutting the flow of potassium, leading to a loss of function; or by increasing potassium flow, leading to an excess gain of function. Patients demonstrating a loss of function had their first epileptic seizures starting at the age of around one, but the attacks ceased during childhood or in the patient's teenage years. For patients with increased function, however, epileptic seizures began even earlier and recurred into adulthood.
Paper Context: A dominant-negative effect of the Pro405Leu and Ile263Thr mutants on wild-type K V 1.2 was seen when a constant amount of cRNA for the wild-type channel (amount 1 in b) was injected with either water or increasing amounts of cRNA for the mutant channels (top: Pro405Leu: ratio 1:1, n = 47; ratio 1:2, n = 40; ratio 1:4, n = 36; bottom: Ile263Thr: ratio 1:1, n = 34; ratio 1:2, n = 42; ratio 1:4, n = 38). Coexpression of Pro405Leu or Ile263Thr and wild-type channel led to a significant reduction in the current amplitude in comparison to expression of wild-type channel alone (indicated by an asterisk). Groups were statistically different (one-way ANOVA, P < 0.001; post-hoc Dunn's method, P < 0.05).