Genetic Profile of Indian Pheochromocytoma and Paraganglioma Patients – A Single Institutional Study

BACKGROUND AND AIMS: Pheochromocytomas (PCCs) and Paragangliomas (PGL) are rare catecholamine producing tumors that may present in sporadic or familial settings. Despite vast strides in understanding of PCC/PGL genetics in the last two decades, there is a dearth of information from India. The aim here is to study the prevalence of genetic mutations in Indian PCC/PGL patients. SETTINGS AND DESIGN: Tertiary care academic hospital; prospective study. METHODS: 50 histopathologically diagnosed PCC/PGL patients formed the study group. Clinical, biochemical, pathological attributes and outcomes were documented and the phenotype was compared to the genotype. Succinyl dehydrogenase (SDH), Re-Arranged during Transfection (RET), Von-Hippel-Lindau (VHL) and NeuroFibromatosis-1 (NF1) mutations were studied. Additionally, immunohistochemisty for SDHB was also done, and the results compared to mutational analysis of SDH by MLPA (Multiplex Ligation-dependent Probe Activation). STATISTICAL ANALYSIS: Independent samples t-test and Fisher's exact test were used as appropriate. P values ≤0.05 were considered statistically significant. RESULTS: The mean age was 34.3 years. Of the 50 patients, 27 were males and 23 females. 10 patients (20%) in all were detected to have a genetic mutation. 6 patients possessed a RET mutation, while two had VHL mutations. No patient presented with a NF1 mutation. 2 patients had a SDH mutation, and Immunohistochemistry for SDHB correlated with mutational analysis for these patients. CONCLUSIONS: The proportion of patients with a familial variant of PCC/PGL is more than what the historic “Rule of Ten” suggests. Our study found that one in five patients have a genetic mutation. PCC/PGL patients with genetic mutations not only require more stringent follow-up, but also screening of family members.