Background: VEXAS syndrome is a rare disease, characterized by heterogeneous rheumatologic and hematologic manifestations, driven by somatic mutations within gene UBA1.

Objectives: To comprehensively characterize the clinical profile and disease course of patients with VEXAS syndrome.

Methods: A nationwide survey across Spanish public hospitals with rheumatologic units identified patients with VEXAS syndrome with confirmed UBA1 gene mutations, diagnosed between December 2020 – December 2024. Demographic, clinical, laboratory, and treatment data were collected from medical records in a standardized form.

Results: We identified 47 patients, all caucasian males. Mean age at symptom onset was 67.18 years (±SD 10.02, range 40-92), while mean age at final diagnosis was 72.52 years (±SD 8.92, range 46.5-93). The median time from symptom onset to final diagnosis was 5 years (IQR 2-9) and to rheumatology referral was 1 year (IQR 0.5-4).

Most frequent previously consider diagnosis are summarized in Table 1.

Main features observed were skin lesions (89.36%), non-infectious fever (78.72%), constitutional syndrome (76.59%), arthritis (74.47%), ocular involvement (59.57%) and chondritis (46.81%). Other hallmark characteristics include pulmonary involvement (34.04%), thrombosis (31.91%), and renal involvement (23.40%). Supplementary information regarding clinical manifestations is gathered in Table 2.

Average haemoglobin was 10 gr/dL (±SD 1.53) and average mean corpuscular volume was 110 fL (±SD 10.06). Thrombocytopenia and leukopenia were present in 46.80% of the patients. Furthermore, 46.80% met criteria for MDS, 25.53% for MGUS and 14.89% for MM. Bone marrow studies showed vacuoles in 72.34% of the cases. Mutations affecting UBA1 gene were present in 100% of the patients registered. All patients received therapy with glucocorticoids. Additional treatments included methotrexate (42.6%), JAK inhibitors (27.7%), IL-6 inhibitors (23.4%), and IL-1 inhibitors (19.2%). One patient underwent hematopoietic stem cell transplant.

Conclusion: The findings of this series, although consistent with those observed in other national registries, present certain particularities, such as a high rate of joint (75%) or renal (23%) involvement, as well as a non-negligible percentage (25%) of MGUS which, most probably, represent the clinical profile more frequently seen in rheumatology units.

REFERENCES: [1] Beck DB, Ferrada MA, Sikora KA, Ombrello AK, Collins JC, Pei W, et al. Somatic mutations in UBA1 and severe adult-onset autoinflammatory disease. N Engl J Med. 2020 Dec 31;383(27):2628-2638. doi: 10.1056/NEJMoa2026834. Epub 2020 Oct 27. PMID: 33108101; PMCID: PMC7847551.

[2] Georgin-Lavialle S, Terrier B, Guedon AF, Heiblig M, Comont T, Lazaro E, et al. Further characterization of clinical and laboratory features in VEXAS syndrome: large-scale analysis of a multicentre case series of 116 French patients. Br J Dermatol. 2022 Mar;186(3):564-574. doi: 10.1111/bjd.20805. Epub 2021 Nov 28. PMID: 34632574.

Acknowledgements: NIL.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.