Pheochromocytoma: Impact of genetic testing on clinical practice in Vietnam

Introduction: 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. Methods: 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. Results: 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. Conclusions: 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.