Although the association of pheo/PGLs and an MEN1-like syndrome has been described in the literature in 13 cases, in only four of these have MEN1 mutations been identified (23, –, 25), and none of them has been studied for LOH in the pheochromocytoma tissue. The gene discussed is MEN1; the disease is hereditary pheochromocytoma-paraganglioma.