The exonuclease, three prime repair exonuclease 1 (TREX1), degrades cytosolic DNA (Mazur and Perrino, 1999; Crow et al., 2006) and its deficiency leads to multiple inflammatory and autoimmune diseases such as systemic lupus erythematosus, Aicardi–Goutieres syndrome, and familial chilblain lupus (Rice et al., 2015). This evidence concerns the gene TREX1 and familial chilblain lupus.