In a study where patients carrying RET proto-oncogene mutations considered ‘Low Risk’ by ATA were examined, it was found that for codons 533, 609, 611, 791 and 804, the appearance of MTC before age 20 was ≤10%, while for codon 533, it was 63% by age 50; the estimated median age at diagnosis was 47 years (23). Here, RET is linked to medullary thyroid gland carcinoma.