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).

Immunodeficiency-79 (IMD79) is an autosomal recessive disorder characterized by childhood onset of recurrent and recalcitrant skin warts due to uncontrolled viral infection with human papillomavirus (HPV). Some patients may also have recurrent respiratory infections beginning in childhood, but the phenotype overall is mild compared to other primary immunodeficiencies. Patients may not come to attention until adulthood. Laboratory studies show absence of the CD4 antigen on T cells, monocytes, and dendritic cells, with variable secondary abnormalities in B cells and NK cells due to lack of CD4+ T cells (summary by Lisco et al., 2021).