FH and von Hippel-Lindau disease: The pseudohypoxic cluster is characterised by constitutive activation of hypoxia inducible factors leading to inhibition of oxidative phosphorylation and activation of glycolytic pathway via the Warburg effect – includes the succinate dehydrogenase (SDH) subunit B, C, D, complex assembly factor 2 (AF2, also called SDH5) and A, Von Hippel-Lindau disease (VHL), Hypoxia Inducible Factor (HIF) Type 2 and fumarate hydratase (FH) genes.