Bierut et al., 2010 report a modest association (p < 10–6) with a SNP (rs10224675) in TPK1. TPK1 encodes thiamine pyrophosphokinase 1 which catalyzes the conversion of thiamine to thiamine pyrophosphate and plays a central role in thiamine metabolism (Fig. 1 and Table 3). Alcohol dependence is a well-known factor that can lead to a thiamine deficiency (Singleton and Martin, 2001). Thiamine deficiency is a known cause of Wernicke's Encephalopathy and Korsakoff's Syndrome(WKS) that is commonly associated with chronic alcohol dependence (Sutherland et al., 2014). Wernicke’s Encephalopathy is an acute life– threatening neurologic disorder that includes mental confusion, paralysis of the nerves that move the eyes (i.e., oculomotor disturbances), and an impaired ability to coordinate movements, particularly of the lower extremities (i.e., ataxia). Whereas, Korsakoff's Psychosis is a chronic neuropsychiatric syndrome characterized by behavioral abnormalities and memory impairments. Approximately 80–90 percent of alcoholics with Wernicke's Encephalopathy develop Korsakoff's psychosis (Butterworth, 1989). In economically advantaged countries such as the United States, where other forms of malnutrition are uncommon, thiamine deficiency and the resulting WKS occur most commonly among alcoholics. In postmortem
