Epidermodysplasia verruciformis-4 is an autosomal recessive immunologic disorder characterized by increased susceptibility to certain human papilloma viruses (HPV) that cause warts and skin lesions. Affected individuals present in childhood with disseminated flat warts and psoriatic-like lesions that do not respond to treatment. Immunologic workup shows defects in T-cell development and signaling (summary by Crequer et al., 2012). For a discussion of genetic heterogeneity of susceptibility to epidermodysplasia verruciformis, see EV1 (226400).