SERINC2 on Chr1 is also a genome-wide significant and replicable risk gene for alcohol dependence in the population of European descent. SERINC2 encodes serine incorporator 2 (Serinc2) that belongs to a cell membrane carrier protein family of Serinc1–5. High concentration of Serinc2 is seen in neurons of the human hippocampus and cerebral cortex (62) and also in the rodent brain in the present study. It serves as an effector molecule that incorporates serine into membranes and facilitates the synthesis of two serine-derived membrane lipids, phosphatidylserine and sphingolipids (long-chain amino alcohols) (63). Phosphatidylserine supplement has been approved by the U.S. Food and Drug Administration to treat memory deficit disorders such as Alzheimer's disease and other forms of dementia, to support healthy cognitive function during aging, and to remediate cognitive deficits as a result of heavy drinking and cigarette smoking. SERINC2 might also influence alcohol dependence via the glutaminergic pathway that is known to play important roles in alcohol intoxication and withdrawal (64). SERINC2 is enriched with numerous structural variants (see NCBI dbSNP). The three genome-wide significant risk SNPs are also located
