SAMHD1 was originally described as a factor whose mutations are associated with an autoimmune conditions designated Aicardi–Goutières syndrome (AGS) with clinical manifestations resembling congenital viral infection and characterized by a high expression of type I interferon (IFN) and upregulation of IFN-stimulated genes [29]. The gene discussed is IFNA1; the disease is Aicardi-Goutieres syndrome.