AGS patients with SAMHD1 mutations do not display an accumulation of rNMPs (Lim et al, 2015), but the activation of an IFN response is similarly evoked by cGAS‐STING‐mediated sensing of endogenous DNA species in the cytoplasm (Coquel et al, 2018). The gene discussed is STING1; the disease is Aicardi-Goutieres syndrome.