Pheochromocytoma: Impact of genetic testing on clinical practice in Vietnam

Germline mutations in predisposing genes have been found in 30-40% of pheochromocytoma/paraganglioma patients. Screening for inherited genetic mutations provide clinicians with mutation-positive patient management strategies in addition to identifying family members at risk of disease. However, genetic testing for pheochromocytoma has not been performed widely in Vietnam. Seven patients diagnosed with pheochromocytoma in Vietnam underwent germline genetic testing in known pheochromocytoma-associated genes by direct sequencing. When a germline mutation was identified the first-degree relatives were counseled and offered genetic testing for the inherited mutation. Mutations were found in five of seven cases and all mutations were in RET proto-oncogene codon 634 indicating a high risk of developing aggressive medullary thyroid cancer and in some cases leading to prophylactic thyroidectomy as recommended. Genetic testing plays an essential role in the clinical management of pheochromocytoma patients. Genetic results have significantly changed the clinical approach in these patients and identified ‘at risk’ family members.