Quick answer
Some rare diseases are difficult to diagnose not because the test is unavailable but because nobody thinks of them. VEXAS syndrome — vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic — was first described only in 2020, is caused by somatic UBA1 mutations in blood cells, and presents as a stubborn combination of fever, rash, cartilage inflammation, anaemia and low platelets. A man in his late fifties at Renji Hospital had lived with it for three years, passing through three hospitals and five departments before reaching intensive care. The rheumatology team suspected the diagnosis, built its own sequencing assay, and confirmed it within a week from tiny samples of blood, hair and nail [1][2][5].
Key takeaways
- Patient: man in his late fifties with fever, rash, anaemia, arthritis, pneumonia and ear and nasal cartilage redness [2].
- Prior course: three years, three hospitals, five departments, one intensive care admission, multiple transfusions [1][2].
- Earlier label: relapsing polychondritis, which did not respond to treatment [2].
- Diagnosis: somatic UBA1 mutation detected by an in-house sequencing method, using the department's PCR and sequencing platforms [1][3][5].
- Turnaround: samples collected and tested overnight, result within a week, at no charge to the patient [2].
Why somatic mutations are harder to find than inherited ones
An inherited variant is present in every cell at roughly 50% or 100% frequency, which is easy to detect. A somatic mutation in a blood disorder may sit in a small fraction of cells, so a routine panel can miss it, and testing needs tissue where the mutant clone is present. That is why the team used not only blood but hair and nail — tissues that let them distinguish a somatic blood mutation from a constitutional one [2][5].
The hospital describes the approach as a sequencing method designed within its own department, which matters practically: commercial rare-disease panels rarely include newly described genes, and a bespoke assay can be run quickly and cheaply when the clinical suspicion is specific [1][5].
What a diagnosis changes, and what it does not
For this patient the diagnosis ended three years of empirical treatment, some of it harmful — high-dose steroids for a presumed autoimmune disease in a man who also had recurrent infection. It also identified a condition with a known natural history and, for suitable patients, a curative option in stem cell transplantation [2][5].
VEXAS has no approved targeted therapy. Management is immunosuppression to control inflammation, with the constant trade-off against infection, and haematological progression is common; allogeneic transplantation is the only curative approach and carries substantial risk in a population that is often older and comorbid. The specific technical details of the in-house assay, its validation and its sensitivity are not described in the sources reviewed, so it should be understood as a case report of a diagnostic pathway rather than a validated test others can adopt [2][5].
The condition in context: VEXAS syndrome
It sits at the boundary between rheumatology and haematology, which is exactly why it is missed.
| Region | What the data shows | Source |
|---|---|---|
| First description | Defined by the US National Institutes of Health in December 2020 [2]. | MedSci [2] |
| Typical patient | Mostly male, median onset around 64 years [2]. | MedSci [2] |
| Diagnostic clue | Refractory inflammatory disease with progressively worsening haematological abnormalities [2]. | MedSci [2] |
Because the presentation mimics common rheumatological diseases, the diagnostic trigger is suspicion rather than symptoms [1][2].
Why it matters
| Potential | What the report suggests | Source |
|---|---|---|
| Speed | Result within a week of suspicion [2]. | [2] |
| Access | In-house assay avoided a commercial test delay [5]. | [5] |
| Caution | Assay validation not described; no targeted therapy [2]. | [2] |
Availability and limits
- This is an editorial summary of hospital case reporting, not a diagnostic service offer [1][2].
- The in-house assay's performance characteristics are not published [5].
- Somatic mutation testing requires appropriate tissue, not serum alone [2].
- No approved targeted treatment exists for VEXAS [2].
- Specialist rheumatology and haematology co-management is required, and a rare disease genetic testing pathway is needed to reach the assay [4][5].
What to ask before booking
| Question | Why it matters |
|---|---|
| Has a somatic mutation been considered, not only inherited variants? | Routine panels may miss low-fraction mutations [2]. |
| Should hair or nail be tested alongside blood? | It distinguishes somatic from constitutional variants [2]. |
| Which department handles foreign patients, and in what language? | Renji is a working hospital we do not book; confirm international-department coordination and language support. |
| What treatment is available if the diagnosis is confirmed? | Management is immunosuppressive, not curative [5]. |
Questions patients ask
What is VEXAS syndrome?
An adult-onset autoinflammatory disease caused by somatic UBA1 mutations in blood cells, first described in 2020, presenting with fever, rash, cartilage inflammation and progressive haematological abnormalities [2].
How was it diagnosed here?
The rheumatology team suspected it clinically and used an in-house sequencing method on small samples of blood, hair and nail, obtaining a result within a week [1][2].
Why is it often missed?
It mimics common rheumatological disease and requires testing for a somatic mutation that routine panels may not detect [2].
Is there a treatment?
No approved targeted therapy; management is immunosuppression, with stem cell transplantation the only curative option for selected patients [5].
Is this relevant to international patients?
It is useful context for China's rare disease diagnostics. Renji is a working hospital we do not book — contact its international department directly [1].