Table 1.

Genes encoding mitochondrial proteins implicated in pheochromocytomas/paragangliomas (PPGL) susceptibility.

Genes	Enzyme	Phenotype	Mutation Frequency
SDHA SDHB SDHC SDHD SDHAF2	Succinate dehydrogenase	Paraganglioma/pheochromocytoma Renal cell carcinoma Gastrointestinal stromal tumour Gastrointestinal stromal tumour	20% 0.05–0.2% 12% (adult forms) 70% (paediatric forms)
FH	Fumarate hydratase	HRLCC syndrome Paraganglioma	70–90% 1%
MDH2	Malate dehydrogenase	Paraganglioma	One patient