Tackling the diagnosis of haploinsufficiency (HA20) in children: challenges of a highly variable clinical and genetic spectrum
Authors' conclusion
HA20 should be suspected in children with fever and gastrointestinal inflammation, even in the absence of oral/genital ulcers. Early onset colitis, the distinctive morphology of mucosal ulcers and a positive family history for HA20 are particularly suggestive.
Study context
- Population
- Patients with paediatric-onset (before 18 years) A20 haploinsufficiency (HA20) carrying a TNFAIP3 mutation, from 11 unrelated families, French national paediatric rheumatology network11 unrelated families
- Participants
- 17 patients
- Outcome
- Clinical, biological and genetic characteristics of paediatric-onset HA20
Methodological detailsmulticentre, observational
- Multicentre
- Observational
Main finding
As reported in the abstract
Clinical characteristics at onset
- Median age at symptom onset (range 1 month-17 years)
- 3 years
- Median diagnostic delay (range 1-43 years)
- 9.7 years
- Initial oral ulcers
- 64.7%
- Initial fever
- 64.7%
- Initial abdominal pain
- 47.1%
- Initial arthralgia
- 35.3%
- Initial skin eruption
- 17.6%
- Genital ulcers at onset
- 17.6%
- Genital ulcers during follow-up
- 52.9%
- Abdominal pain (overall)
- 76.5%
- Colitis
- 35.3%
- Arthralgia (overall)
- 52.9%
- Arthritis
- 29.4%
- Skin eruption (overall)
- 41.2%
- Lymphadenopathy
- 35.3%
- Hepatomegaly
- 11.8%
- Headache
- 17.6%
- Uveitis
- 5.9%
- Novel TNFAIP3 variants identified
- 3
Observational data: associations, not effects.
Further findings
Treatment efficacy
- Colchicine effective as monotherapy
- 40%
- Adalimumab efficacy
- 60%
- Infliximab efficacy
- 100%
- TNFi showed the highest efficacy
Original publication
Tackling the diagnosis of HA20 in children: challenges of a highly variable clinical and genetic spectrum. RMD Open. Published 25 February 2026. doi:10.
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