Novel germline variant of TMEM127 gene in a patient with familial pheochromocytoma

Abstract

Summary

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare tumours with a heterogeneous genetic background. Up to 40% of apparently sporadic PCC/PGL cases carry 1 of the 12 gene germline mutations conferring genetic susceptibility to PCC/PGL. Although the precise mechanisms are unclear, TMEM127 is one of the rare responsible genes for PCC/PGL. Here we report the case of a patient with familial PCC having a novel TMEM127 variant (c.119C > T, p.S40F). In silico prediction analysis to evaluate the functional significance of this variant suggested that it is a disease-causing variant. A PCC on the left side was considered to be the dominant lesion, and unilateral adrenalectomy was performed. The histopathologic findings were consistent with benign PCC. A loss of heterogeneity of the TMEM127 variant was detected in the surgically removed tumour.

Learning points:

• c.119C > T (p.S40F) is a novel TMEM127 variant that can cause pheochromocytoma.

• The tumour showed loss of heterozygosity of this TMEM127 variant.

• The clinical phenotype of this mutation is putative bilateral pheochromocytoma in the 4th decade.

• Unilateral adrenalectomy may be performed as the initial surgery in such cases.