The exciting potential for targeted HIF2α inhibition outside of VHL disease was also highlighted in a recent report describing the use of belzutifan in an adolescent patient with Pacak–Zhuang syndrome, a tumor predisposition syndrome caused by a gain-of-function mutation in the HIF2α EPAS gene, most often via post-zygotic somatic mosaicism [53]. The gene discussed is EPAS1; the disease is BAP1-related tumor predisposition syndrome.