Interestingly, additional phenotypes including John Cunningham (JC)-virus induced progressive multifocal leukoencephalopathy (11), Orf infection (6), Immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX)-like syndromes with CMC (4, 15), and a combined immunodeficiency (CID) without CMC (16) have been associated with STAT1 GOF mutations, but remain unexplained from a pathophysiological point-of-view and therefore require further investigation. The gene discussed is STAT1; the disease is combined immunodeficiency.