RET and medullary thyroid gland carcinoma: There is a genotype–phenotype correlation between RET mutations and MEN2A, MEN2B, and MTC‐only, with: the majority of MEN2A patients having RET germline mutations involving codons 609, 611, 618, or 620 of exon 10, or codon 634 of exon 11; MEN2B patients having mutations of codon 918; and MTC‐only patients having mutations involving codons 618, 790, 791, or 804 (Raue & Frank‐Raue, 2012).