GJB6 and Alzheimer disease: In post-mortem AD brain samples and in murine AD models, astroglial Cx30 and particularly Cx43 in reactive astrocytes accumulate significantly around β-amyloid plaques [24,25,26], and overactivation of Cx43 hemichannels has been linked to excessive ATP and glutamate release with toxic consequences for neurons [26,27,28,29,30].