On the other hand, stress-related (i.e., cortisol-induced) transcriptional activation of human PER1 was reduced in a type of human blood cells (i.e., B-lymphoblastoid cells) that carried an altered form of the PER1 gene (i.e., the rs3027172 genotype), which has been associated with an increased risk of alcoholism (Dong et al. 2011). This evidence concerns the gene PER1 and alcohol dependence.