Penetrance and clinical features of pheochromocytoma in a six-generation family carrying a germline TMEM127 mutation.

Context: The phenotype of familial pheochromocytoma (PHEO) associated with germline TMEM127 mutations (TMEM127-related PHEO) has not been clearly defined. Objective: This study aimed to investigate the penetrance, full phenotypic spectrum and effectiveness of clinical/genetic screening in TMEM127-related PHEO. Design, Setting, and Participants: Clinical and genetic screening, and genetic counseling were offered to 151 individuals from a six-generation family carrying a TMEM127 germline mutation in a referral center. Intervention and Main Outcome Measures: TMEM127 genetic testing was offered to at-risk relatives and clinical surveillance for pheochromocytoma was performed in mutation-positive carriers. Results: Forty seven individuals carried the c.410-2A>C TMEM127 mutation. Clinical data were obtained from 34 TMEM127-mutation carriers followed up for 8.7 ± 8.1 years (range, 1–20 y). Pheochromocytoma was diagnosed in 11 carriers (32%) at a median age of 43 years. In nine patients, symptoms started at 29 ye...