In addition, our own finding of NPNT as an exquisitely selective ZG protein, 3.6-fold upregulated in ZG compared with ZF when adjacent to a pheochromocytoma, but diminished or absent when adjacent to an APA, suggests the disappearance of NPNT when physiological aldosterone secretion is not required. This evidence concerns the gene NPNT and hereditary pheochromocytoma-paraganglioma.