DSG1 and Feingold syndrome: The IgG4 anti-Dsg1 autoantibody response is restricted to FS patients (Warren et al., 2003; Qaqish et al., 2009), whereas the non-pathogenic anti-Dsg1 IgG1 antibodies are detected in disease-free inhabitants of Brazilian endemic populations in the Limao Verde (LV) Amerindian reservation (Warren et al., 2000; Warren et al., 2003; Qaqish et al., 2009).