has material basis in germline mutation in TKFC immunodeficiency disease isolated immunodeficiency, TKFC-related https://github.com/monarch-initiative/mondo/issues/10647 TKFC deficiency, isolated presentation Any immunodeficiency disease in which the cause of the disease is a variation in the TKFC gene. It is characterized by chronic active Epstein-Barr virus disease, multiple bacterial and viral infections, hypogammaglobulinemia, near-absent natural killer cells, and decreased memory B cells, without the multisystem features of triokinase and FMN cyclase deficiency syndrome. MONDO:1060318