The two sequence polymorphisms for which we found an association with EEB are located in regions of the Drd4 gene, the promoter (ID15) and third intracellular loop-coding region (SNP830), that harbour personality-associated variants in humans, monkeys and horses (Kluger et al. 2002; Schinka et al. 2002; Reif & Lesch 2003; van Gestel & Van Broeckhoven 2003; Savitz & Ramesar 2004; Momozawa et al. 2005; Ebstein 2006; Bailey et al. 2007). This evidence concerns the gene DRD4 and epidermolysis bullosa simplex.