Haploinsufficiency of A20 (HA20)
Haploinsufficiency of A20 (HA20) is a recently discovered inherited autoinflammatory syndrome caused by loss-of-function mutations in the TNFAIP3 gene. This gene encodes A20, a protein that acts as a key brake on inflammation in the body. When A20 is in short supply, the NF-κB signaling pathway becomes overactive, leading to systemic inflammation and features that closely resemble Behçet disease.
At Haute-Derma, we treat HA20 as a complex multisystem disease. Recognizing it early spares patients years of misdiagnosis and gives them targeted treatment that prevents recurrent ulcers and protects their overall health.
Our Approach to Treating HA20
Our specialists focus on restoring immune balance by controlling the excess inflammatory cytokines that result from A20 deficiency. HA20 often starts in early childhood with painful ulcers that make eating and daily life much harder.
We use advanced genetic testing to tell HA20 apart from ordinary Behçet disease and then tailor treatment with biologic therapy. Our main goal at Haute-Derma is to help patients become symptom-free and to prevent serious complications affecting the blood vessels and digestive tract.
Our HA20 care pathway includes:
- TNFAIP3 gene sequencing to identify the disease-causing mutation.
- Anti-TNF-alpha or anti-IL-1 biologic therapy to suppress systemic inflammation.
- Multidisciplinary follow-up (gastroenterology, rheumatology, ophthalmology) to manage internal organ involvement.
How We Diagnose HA20 at Haute-Derma
Because HA20 looks so much like Behçet disease, we follow a careful differential diagnosis process:
- Assessing mucosal ulcers: looking for recurrent mouth and genital ulcers that began very early, often before age 10.
- Checking the skin and joints: looking for erythema nodosum, acne-like lesions and recurring arthritis in several joints.
- Screening for digestive symptoms: checking for Crohn-like bowel inflammation, which is more common in HA20 than in classic Behçet disease.
- Immunologic tests: tracking inflammatory markers (CRP, ESR) and testing for autoantibodies to rule out other autoimmune diseases.
- Genetic analysis (NGS): the decisive step, identifying a TNFAIP3 mutation to confirm HA20 with the greatest accuracy.
How HA20 Is Treated at Haute-Derma
Our treatment aims to rein in the overactive NF-κB pathway:
- Anti-TNF-alpha therapy: TNF-blocking biologics (such as adalimumab or infliximab) are often our first choice. They work well to heal mucosal ulcers and control arthritis.
- Anti-interleukin-1 (IL-1) therapy: considered when high fevers and systemic inflammation dominate, to quickly damp down cytokine storms.
- Colchicine and immunomodulators: help control milder symptoms and keep the disease stable between flares.
- Specialized local ulcer care: targeted topical treatments relieve pain and help the mucosa heal quickly.
- Family genetic counseling: because HA20 is inherited in a dominant pattern, we offer screening for family members so the condition can be found and treated early.
