The novel variants K666E, IVS9-11G-->A, D631V in cis with H665Q, D631E (with C634Y), E623K (in trans with C618S), 616delGAG (in trans with C609Y), Y606C, C630R, and R635-T636insELCR;T636P were detected in patients with various clinical presentations ranging from thyroid goiter, medullary thyroid carcinoma, and pheochromocytoma to classic multiple endocrine neoplasia type 2A.
An association between pheochromocytoma expression and amino acid substitutions at codon 618 was observed as follows: 0 of 7 patients with C618F, 5 of 21 patients with C618G (24%), 11 of 27 patients with C618R (41%), 7 of 41 patients with C618S (17%), and 0 of 9 patients with C618Y (P = .04.)