SAMHD1 is mutated in cancer (Clifford et al, 2014; Merati et al, 2015; Rentoft et al, 2016) and in the neurodegenerative autoimmune disorder Aicardi–Goutières syndrome in which aberrant nucleic acids accumulate, inducing innate immunity (Ballana & Este, 2015). Here, SAMHD1 is linked to Aicardi-Goutieres syndrome.