SAMHD1 and Aicardi-Goutieres syndrome: This data, in addition to the presumed autoimmune nature of AGS and the fact that genes that cause AGS (i.e., TREX1 and SAMHD1) are allelic to those that can cause SLE and FCL, warrants further study into the association between heterozygous mutations in AGS-related genes and autoimmune disease.