STK4 and Netherton syndrome: A number of primary immunodeficiency disorders that include cutaneous warts as a major feature have been defined and include: epidermodysplasia verruciformis (EVER1 and EVER2 deficiency), WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis syndrome—CXCR4 deficiency), autosomal recessive hyper-IgE syndrome (dedicator of cytokines 8 deficiency, DOCK8), idiopathic CD4 lymphopenia, GATA2 deficiency, Netherton syndrome (serine protease inhibitor Kazal-type 5 deficiency, SPINK5), and mammalian sterile 20-like protein (serine-threonine kinase 4 deficiency, STK4) [51].