Several adaptive responses to hypoxia are mimicked by hereditary paraganglioma (PGL), a human genetic disorder characterized by the development of tumors from the hypoxia-sensitive paraganglionic tissues and caused by germ line heterozygous inactivating mutations in the nuclear-encoded SDHB, SDHC or SDHD subunit genes of mitochondrial complex II (succinate dehydrogenase; SDH; succinate-ubiquinone oxidoreductase) [2], [3]. This evidence concerns the gene SDHB and hereditary disease.