MARK2 and early-onset autosomal dominant Alzheimer disease: Glycogen Synthase Kinase-3 Beta (GSK3β), a multifunctional serine/threonine kinase, plays a central role in cellular signaling pathways and autophagy regulation, processes critical to neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and Amyotrophic Lateral Sclerosis (ALS).