DYRK1A and Dravet syndrome: Many studies using different lines of transgenic mice have shown that the additional expression of DYRK1A in a normal mouse, which mimics trisomy in human DS, is sufficient to cause abnormalities in learning and memory as well as brain structure, strongly suggesting a central function for DYRK1A in the mental retardation associated with DS (Ahn et al., 2006; Altafaj et al., 2001).