SAMHD1 and Aicardi-Goutieres syndrome: The AGS is caused by the mutation on any of the 3 domains of the H2 ribonuclease [80], in DNA exonuclease 1 (TREX1) [81], the sterile alpha motif domain and HD containing protein 1 (SAMHD1) [82], or adenosine deaminases acting on RNA (ADAR1) [83].