We focus on GABRA2, because polymorphisms in GABRA2 have been associated with adult alcohol dependence across multiple independent studies (Covault, Gelernter et al. 2004; Edenberg, Dick et al. 2004; Fehr, Sander et al. 2006; Enoch 2008; Soyka, Preuss et al. 2008). However, the two reports that have tested for association with alcohol dependence in younger samples have not found evidence for this association (Dick, Bierut et al. 2006; Sakai, Stallings et al. 2010). These findings are consistent with twin data in which there is significant heritability for alcohol dependence in adulthood (in the range of 50–60%) (Dick Prescott et al. 2009); but little evidence of genetic influence on alcohol dependence symptoms in early adolescence (< age 15) (Rose, Dick et al. 2004; Knopik, Heath et al. 2009). A major limitation of the literature on GABRA2 is that no studies of which we are aware have used longitudinal data to explicitly test the unfolding of risk associated with GABRA2 across development. In the current analyses, we used longitudinal data from individuals with up to three assessments between the ages of 14
