CHRNA4 and nicotine dependence: A more recently expanded GWAS of ND from the Nicotine Dependence GenOmics Consortium (iNDiGO; Quach et al., 2020) provided further evidence for a top variant association in CHRNA5 on chromosome 15 (rs16969968), and a significantly associated variant (rs151176846) in CHRNA4 on chromosome 20 (CHRNA4) that was associated with ND in an earlier GWAS (Hancock et al., 2015).