Searching for variants with evidence of regulatory functions, we have reported interactions between CHRNA5 and CHRNA3 enhancer variants (tagged by rs880395 and rs1948, respectively) and rs16969968, forming 3-SNP haplotypes and diplotypes that may more accurately reflect the cluster’s combined effects on nicotine dependence (Barrie et al., Hum Mutat 38:112–9, 2017). The gene discussed is CHRNA5; the disease is nicotine dependence.