et al., 2005c) were further confirmed in a later study by Webb et al. (2011). Webb and colleagues discovered that loci coding for CYP2E1 were highly correlated with LR measured after an alcohol challenge. Kuo and colleagues observed an association between GABAnergic enzyme gene markers, linked with sedative and depressant effects of alcohol, and SRED (Kuo et al., 2009). In a sample of Native Americans, loci on six chromosomes were found to overlap with genes associated with SRED (Ehlers et al., 2010). SRE measured during the early drinking phase (SRED) has been found to be heritable among a sample of adolescents (Schuckit et al., 2005a). However, within that sample, SRED may represent total SRE as they may not yet be regular drinkers (in order to measure SRRD) or experienced their period of heaviest drinking (SRHD). The lack of significant heritability of the SRED score in the present study suggests that genetic influence on initial response to alcohol may be limited (Rose et al., 2001). Alternatively, a lapse in time between initiation of drinking and the study could have resulted in over-estimation of LR, and consequently affected the interpretation of the results (Morean and Corbin, 2008).
