IL1B and Pseudoxanthoma elasticum: For this, we performed a preliminary IL1B stimulation experiment in dermal fibroblasts of patients with an extremely mild and severe cardiovascular phenotype and healthy controls, which showed a significant upregulation of IL1B in severely affected PXE patients compared to mildly affected patients (eightfold; p < 0.001, 95%CI: 2.9–24.6) and to healthy controls (51-fold; p < 0.001, 95%CI: 24.2–107.2; Supplementary Figure 5).