Source: International consensus on initial screening and follow-up of asymptomatic SDHx mutation carriers


Approximately 20% of patients diagnosed with a phaeochromocytoma or paraganglioma carry a germline mutation in one of the succinate dehydrogenase (SDHx) genes (SDHA, SDHB, SDHC and SDHD), which encode the four subunits of the SDH enzyme. Mutations in the SDHx genes (SDHASDHBSDHC and SDHD), which encode the four subunits of the mitochondrial enzyme succinate dehydrogenase (SDH), are associated with a predisposition for developing hereditary phaeochromocytoma and/or paraganglioma (PPGL)1. 

Conclusion: It is strongly recommended that asymptomatic carriers of SDHx mutations (detected by familial genetic testing) undergo regular biochemical testing and clinical examination.

It is currently recommended that all patients with a newly discovered PPGL should be offered genetic counselling2. Germline mutations in SDHx genes are responsible for approximately 20% of cases of PPGL and can also be associated with the presence of other SDHx-related tumours1,2,3. PPGL detection at an early stage has a positive effect on outcomes, including survival4. First-degree family members can also benefit from genetic testing but it remains to be determined how to screen and then follow-up the newly detected asymptomatic mutation carriers as no consensus has as yet been established