To the Editor.
—Dr Neumann and colleagues1 describe the importance of genetic testing in disease kindreds. We agree with the authors' findings, but feel further explanation would be helpful.The authors describe two von Hippel-Lindau (VHL) families that were clinically thought to have multiple endocrine neoplasia, type II (MEN-II). It has also been our experience that a small number of VHL mutations predispose to pheochromocytoma, with few other, if any, manifestations of VHL. We have seen nine individuals from three of 80 VHL families, whose sole manifestation of VHL was pheochromocytoma, similar to previous reports.2We also have seen two families in whom the occurrence of pheochromocytoma was frequent, and who were followed clinically as MEN-II families. Closer evaluation of these families revealed some findings compatible with VHL disease. One family was kindred 4942, in which among at-risk patients in three generations, six members had pheochromocytoma and one