A neurologist's guide to VEXAS syndrome: Differentiating somatic autoinflammation from autoimmune mimics

This review characterizes VEXAS syndrome (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) as a prototype of adult-onset autoinflammation that challenges traditional autoimmune paradigms. Driven by constitutive activation of innate myeloid cells via Ubiquitin-Like Modifier Activating Enzyme 1 (UBA1) mutations, VEXAS affects the nervous system in approximately 6-10% of cases. We identify the peripheral nervous system as the primary target (70%), typically manifesting as refractory axonal polyneuropathy, while central involvement may present as neutrophilic meningoencephalitis. Crucially, we highlight the "hematologic paradox"-hyperinflammation co-occurring with macrocytic anemia rather than thrombocytosis-as the key biomarker distinguishing VEXAS from vasculitic mimics, necessitating early genetic sequencing for targeted clone suppression.