VHL and hemoglobin measurement: Deleterious mutations in the VHL gene cause tumors such as hemangioblastomas (HB) of the retina, cerebellum, brainstem, and spine; clear renal cell carcinomas (RCCs); pheochromocytomas (Ph); neuroendocrine tumors (N); endolymphatic sac tumors (ELST); cystadenomas of the epididymus, broad ligament, and pancreas; and cysts in the kidneys and pancreas 1,2).