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TREX1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

TREX1 gene

The TREX1 gene encodes an enzyme that removes damaged DNA to prevent immune system activation, and its dysfunction is associated with several inflammatory and autoimmune conditions.

Normal Function

The TREX1 gene provides instructions for making the three prime repair exonuclease 1 enzyme. This enzyme is a DNA exonuclease, which trims DNA molecules by removing building blocks (nucleotides) from the ends. This process helps remove incorrect or damaged nucleotides created during cell division, DNA repair, and cell death (apoptosis), maintaining the stability of genetic material.

Additionally, the enzyme removes unusual pieces of DNA that might otherwise be mistaken by cells for the genetic material of viral invaders. By clearing these fragments, the enzyme prevents the triggering of unnecessary immune system reactions.

Health Conditions Related to Genetic Changes

Aicardi-Goutières syndrome

Variants in the TREX1 gene have been identified in people with Aicardi-Goutières syndrome, a disorder involving severe brain dysfunction (encephalopathy) and skin lesions. The absence of the three prime repair exonuclease 1 enzyme allows unneeded DNA and RNA to accumulate in cells, which the immune system mistakes for viral invaders, leading to inflammation that damages the brain, skin, and other organs.

Systemic lupus erythematosus

Variants in the TREX1 gene are linked to systemic lupus erythematosus (SLE), specifically a rare form called chilblain lupus. This condition primarily affects the skin, causing joint pain and painful lesions on the fingers, ears, nose, toes, and cheeks that worsen in the cold. The lack of functional enzyme leads to immune system dysfunction characteristic of SLE.

Other disorders

  • Autosomal dominant retinal vasculopathy with cerebral leukodystrophy: A disorder affecting the brain and blood vessels in the retina, caused by immune system dysfunction due to impaired enzyme function.
  • Cryofibrinogenemia: A rare blood disorder where blood plasma becomes cold, causing bluish skin tint or lesions on the hands, feet, ears, nose, and buttocks due to restricted blood flow.

Other Names for This Gene

  • 3' repair exonuclease 1
  • 3'-5' exonuclease TREX1
  • deoxyribonuclease III, dnaQ/mutD-like
  • DNase III
  • DRN3
  • TREX1_HUMAN

Frequently Asked Questions

Yes. Mutations in TREX1 are a known cause of Aicardi‑Goutières syndrome, which often presents in infancy with encephalopathy, characteristic skin rashes, and sometimes calcifications in the brain. Genetic testing (panel or exome sequencing) that includes TREX1 can confirm the diagnosis and guide management.
subset of chilblain lupus is linked to heterozygous TREX1 variants that impair DNA clearance, leading to chronic type‑I interferon activation. Treatment focuses on reducing interferon signaling (e.g., JAK inhibitors like baricitinib) and protecting extremities from cold, alongside standard lupus therapies such as antimalarials and topical steroids.
Because TREX1 mutations can be inherited in an autosomal‑recessive (Aicardi‑Goutières) or autosomal‑dominant (chilblain lupus, retinal vasculopathy) pattern, targeted genetic testing of first‑degree relatives is recommended. Identifying carriers allows early monitoring for skin or neurologic signs and informs reproductive counseling.
Patients with TREX1 loss‑of‑function typically show elevated interferon‑α signatures and increased levels of circulating DNA fragments. Specific assays such as interferon‑stimulated gene expression panels or quantitative PCR for cell‑free DNA can support the diagnosis, especially when combined with genetic results.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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