Loss-of-function mutations in SKIV2L cause trichohepatoenteric syndrome (THES2), a rare inborn error of immunity characterized by intrauterine growth retardation, early-onset chronic diarrhea, brittle hair with trichorrhexis nodosa, skin lesions, and immunodeficiency (11, 12). The gene discussed is SKIC2; the disease is trichohepatoenteric syndrome.