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PTPN22 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PTPN22 gene

The PTPN22 gene encodes a protein that regulates immune system signaling, and specific variants are associated with an increased risk of various autoimmune disorders.

Normal Function

The PTPN22 gene provides instructions for making a protein belonging to the PTP (protein tyrosine phosphatases) family. These proteins regulate signal transduction, a process where signals from outside the cell are relayed to the nucleus to instruct the cell to grow, divide, or mature. The PTPN22 protein specifically helps control the activity of T cells, which are immune cells that identify and defend the body against foreign substances.

Health Conditions Related to Genetic Changes

Vitiligo

The R620W variation in the PTPN22 gene is associated with an increased risk of vitiligo, an autoimmune condition causing patchy loss of skin pigmentation. This variation likely impairs the PTPN22 protein's ability to regulate the immune system, making it difficult to prevent the immune system from attacking the body's own tissues. In vitiligo, the immune system attacks pigment-producing cells called melanocytes.

Other Associated Autoimmune Conditions

Variants in the PTPN22 gene have been studied in relation to several other autoimmune disorders, including:

  • Alopecia areata
  • Autoimmune Addison disease
  • Graves' disease
  • Hashimoto's disease
  • Idiopathic inflammatory myopathy
  • Juvenile idiopathic arthritis
  • Systemic lupus erythematosus
  • Systemic scleroderma
  • Type 1 diabetes

Genomic Location

The PTPN22 gene is located on chromosome 1.

Frequently Asked Questions

No. The variant increases susceptibility (approximately 1.5‑ to 2‑fold for many conditions) but most carriers never develop clinical disease. Environmental triggers, other genes, and random factors also play major roles.
t present, PTPN22 genotype does not alter standard treatment protocols. However, a positive result may prompt clinicians to monitor for additional autoimmune disorders (e.g., thyroid disease, type 1 diabetes) more closely.
Focus on general immune‑supportive measures: maintain a balanced diet, regular moderate exercise, adequate sleep, avoid smoking, and manage stress. Early screening for thyroid function, blood glucose, and skin changes can catch emerging problems when they are most treatable.
Testing can be considered, especially if multiple first‑degree relatives have different autoimmune conditions. A genetics counselor can explain that the R620W variant modestly raises risk but does not guarantee disease, so results are most useful for risk awareness rather than definitive prediction.
Currently there are no FDA‑approved medications that directly modulate PTPN22 activity. Research is ongoing on small‑molecule inhibitors and antisense approaches, but they remain experimental and not available in routine care.
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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