In VEXAS, mutations disrupt protein ubiquitylation in myeloid cells, leading to endoplasmic reticulum stress and activation of the unfolded protein response (UPR) through key pathways: PERK (Protein kinase R-like endoplasmic reticulum kinase), IRE1α (Inositol-requiring enzyme 1 alpha), and ATF6 (Activating transcription factor 6) [15]. This evidence concerns the gene ERN1 and VEXAS syndrome.