KCNQ2 and neurodevelopmental disorder: The M channels are assembled as heterotetramers of Kv7.2, Kv7.3, and Kv7.5 subunits, and play an important role in epilepsy and neurodevelopmental disorders (Kv7.2 and Kv7.3 subunits) (Marrion, 1997; Cooper and Jan, 2003; Wladyka and Kunze, 2006; Cooper, 2012).