In the TMEM127 gene, a missense alteration (NM_017849.4):c.419G>A, p.(Cys140Tyr) was found in a female patient with a personal history of breast cancer diagnosed at 45 years of age presenting with one family member with breast cancer but no individual or family history for pheochromocytoma or paraganglioma. This evidence concerns the gene TMEM127 and pheochromocytoma.