In the full sample, FH+, and FH? subsamples, AUD cases had significantly higher PRS than controls, as expected. The average PRS in AUD cases was higher than that in controls in FH− subsample but not significant, most likely due to the small sample size. Regardless of AUD status, the FH+ subsample had higher PRS than the FH? and FH− subsamples (Table 2). In addition, FH+ (AUD cases and controls combined) had higher PRS than cases in the FH? subsample (Table 2). These results also demonstrated that consideration of family history may be critical in the design of future GWAS of AUD. Family history of AUD can be used to help with the identification of potential AUD cases. For example, an individual may stop heavy drinking at early age due to other conditions such as alcohol liver diseases; but if that individual also has a positive family history of AUD, then they may be at elevated genetic risk for AUD and could potentially be used as proxy cases for AUD in GWAS studies. On the other hand, many family history positive
