GSK3B and Myotonia: It has been shown that the increase in GSK3β in DM1 affects the cyclin D3-CUGBP1 pathway, contributing to the DM1 muscle phenotype (myotonia, atrophy, muscle weakness and myopathy) in DM1 mice [22,23] and muscle weakness, myopathy and anxiety in DMSXL mice [23].