The frameshift variant (p.Ala194fs) was also identified in the same patient in a separate study using Sanger sequencing (reported as p.Ala139Valfs*21 on a different isoform), and was found to nearly completely abolish TREX1 nuclease activity in vitro.30 This variant has been reported in a compound heterozygous case of Aicardi-Goutières syndrome in the DECIPHER database (patient 303873).31 (table 3). Here, TREX1 is linked to Aicardi-Goutières syndrome.