Taken together, these molecular and biochemical features are foundational for understanding the different clinical features in these patients, with paroxysmal hypertension occurring in the context of the adrenergic biochemical phenotype (increased epinephrine and metanephrine) of MEN-2 as compared to sustained hypertension with the noradrenergic biochemical phenotype (increased norepinephrine and normetanephrine) of VHL. This evidence concerns the gene VHL and multiple endocrine neoplasia type 2.