SAMHD1 and Aicardi-Goutieres syndrome 1: AGS is considered a monogenic disease and can be divided into 7 subtypes according to different pathogenic genes: TREX1 (AGS1), RNASEH2B (AGS2), RNASEH2C (AGS3), RNASEH2A (AGS4), SAMHD1 (AGS5), ADAR1 (AGS6) and IFIH1 (AGS7).