A new review published in the World Journal of Pediatrics offers a systematic framework for understanding Behçet's spectrum disorders (BSD), a concept that could transform how clinicians diagnose and treat children with unexplained inflammatory symptoms that resemble Behçet's disease but defy conventional classification. The framework, developed by researchers at Peking Union Medical College Hospital in Beijing, categorizes these disorders into two tiers based on their underlying genetic mechanisms, providing a roadmap for earlier recognition and prioritized genetic testing.
Behçet's disease is a systemic vasculitis characterized by recurrent oral and genital ulcers, but pediatric presentations are often partial or atypical, complicating diagnosis. A growing number of monogenic autoinflammatory disorders produce nearly identical mucocutaneous and gastrointestinal symptoms yet require different therapeutic approaches. This diagnostic overlap frequently leads to misdiagnosis, inappropriate treatment, and prolonged suffering. Although the BSD concept was introduced in 2020 to link these conditions through shared inflammatory pathways, a practical, clinically applicable framework for early recognition and genetic prioritisation in children has remained elusive.
The review, available at https://doi.org/10.1007/s12519-026-01035-4, proposes a tiered classification: 'core Behçet's spectrum disorders' for monogenic diseases that directly converge on Behçet's-defining inflammatory pathways, and 'peripheral BSD' for conditions with partial clinical overlap or indirect mechanistic connections. The core tier comprises monogenic diseases that disrupt NF-κB or JAK-STAT signalling, including HA20 (caused by TNFAIP3 mutations), RELA haploinsufficiency, NFKB1 haploinsufficiency, and ELF4 deficiency. The peripheral tier includes polygenic or multifactorial entities such as recurrent aphthous stomatitis, PFAPA syndrome, DADA2, and trisomy 8-associated disease.
A major highlight is the identification of NF-κB and JAK-STAT as two central inflammatory hubs serving as common denominators across the entire spectrum, providing a rational basis for grouping these diverse disorders. The authors also delineate exclusion criteria to distinguish true spectrum members from phenotypic mimics like LIG4 deficiency and IKBKG mutations, sharpening diagnostic boundaries. Importantly, the framework does not replace existing Behçet's disease criteria but offers a mechanism-oriented lens to prioritise genetic testing in early-onset or atypical paediatric cases, significantly reducing diagnostic odysseys.
Clinically, the BSD framework enables earlier recognition of Behçet-like phenotypes and guides rational genetic testing, allowing targeted therapies such as IL-1, TNF, or JAK inhibitors for specific subsets. It also helps exclude non-spectrum mimics, avoiding unnecessary investigations and expediting effective care. Scientifically, it unifies disparate inflammatory disorders under shared pathogenic axes, fostering collaborative research and paving the way for biomarker discovery and mechanism-based trials.
'We're not saying these are all the same disease—they're not,' the authors said. 'But they converge on the same inflammatory circuits. If a child shows up with recurrent mouth ulcers, fever, and gut inflammation that doesn't quite fit Behçet's criteria, the BSD framework gives us a roadmap for what to test for and why.' They emphasized that the framework is especially valuable in early-onset or atypical cases, where genetic testing can distinguish between conditions that look alike but respond to very different treatments.
This study was supported by the National Key R&D Program of China (2021YFC2702001), National High Level Hospital Clinical Research Funding (2022-PUMCH-B-079), and CAMS Innovation Fund for Medical Sciences (CIFMS) grants (2019-I2M-5-002, 2024-12 M-C&T-B-018).
