Four cell-surface molecules, CD81, occludin (OCLN), claudin 1 (CLDN1), and scavenger receptor class B member 1 (SRB1), are particularly important for HCV cell entry, although only CD81 and OCLN determine the species-specificity of infection (Bartenschlager et al., 2013; Lindenbach and Rice, 2013). The gene discussed is CD81; the disease is infection.