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Living with A20 haploinsufficiency

A genetic immune condition that causes repeated inflammation, with mouth ulcers, fevers, rashes, and stomach and joint problems.

Understanding A20 haploinsufficiency

A20 haploinsufficiency (HA20) is a complex immune condition that causes repeated inflammation and sometimes immune weakness.

The most common signs are painful mouth or genital ulcers, recurring fevers, skin rashes, stomach and bowel problems, and joint pain or arthritis. Less common findings include swollen lymph nodes, liver inflammation, and brain or nerve problems. It varies from person to person, and even within a family, with different body systems affected at different times.

Signs & symptoms

GARD doesn't list a symptom list for this condition yet. The summary describes these as the most common:

  • Painful mouth or genital ulcers
  • Recurrent fevers
  • Skin rashes
  • Stomach or bowel inflammation
  • Joint pain or arthritis
  • Swollen lymph nodes

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Your doctor may refer you to a specialist who knows rare conditions.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

Care & treatment

Care team
A doctor familiar with rare conditions, plus specialists as needed
Expert care
Ask about multidisciplinary care centers for rare conditions
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with rare disease patient organizations for support
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
What can we do to prevent or treat flares of ulcers and fevers?
Which specialists, such as immunology or rheumatology, should be involved?
Should family members be tested?

Quick facts

GARD describes this as a genetic immune condition, but doesn't list a specific gene or inheritance pattern in this record.

Also known as: ha20; ha20 (haploinsufficiency a20); haploinsufficiency of a20

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · A20 haploinsufficiencyGARD ID 26086 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with A20 haploinsufficiency.

Explore the A20 haploinsufficiency blog

Explore research for A20 haploinsufficiency

Explore actively recruiting A20 haploinsufficiency studies with HealthSpark.

HealthSpark

Find actively recruiting studies for A20 haploinsufficiency with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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