Choline Effects - Pre-symptomatic AD

The purpose of this study is to determine the safety and tolerability, as well as the biochemical effects of choline bitartrate over a 6-month treatment period in a moderately sized population harboring at least one copy of the APOE4 gene. APOE is a protein involved in lipid transport. Studies show that the APOE4 variant is strongly associated with an increased risk of Alzheimer's Disease. It is unclear how APOE4 results in an increased risk for AD, but a recent study identified a novel molecular pathway, which showed that APOE4-induced dysfunction of lipid metabolism in neurons by cellular accumulation of unsaturated lipids. The investigators hypothesize that choline supplementation normalizes the APOE4-mediated dysregulation by normalizing the Kennedy pathway in neuronal cells, thus stabilizing the lipid metabolism and concomitantly restoring normal cell function by increasing phosphatidylcholine activity via the Kennedy pathway. To evaluate this, the investigators will test if choline supplementation will decrease the ratio of unsaturated lipids to saturated lipids (the fatty acid desaturation index) in cerebrospinal fluid by 15% and increase phosphatidylcholine by 100%.