The search for specific genes that convey risk for AUD has been an active area of research for several decades. There have been numerous family-based linkage studies of AUD (Agrawal & Bierut 2012; Rietschel & Treutlein 2013; Enoch 2013; Edenberg & Foroud 2014), as well as candidate gene association studies. Robust linkage signals have been found near the cluster of aldehyde dehydrogenase (ALDH) genes on chromosome 12 (Wall, Luczak & Hiller-Sturmhöfel 2016), and alcohol dehydrogenase (ADH) genes on chromosome 4 (Long et al. 1998; Williams et al. 1999), a result that has also been identified by candidate gene association studies (Thomasson et al. 1991; Luo et al. 2006; Macgregor et al. 2009; van Beek, Willemsen, de Moor, Hottenga & Boomsma 2010; Li, Zhao & Gelernter 2011, 2012).
