A 35-year-old woman with medullary thyroid carcinoma undergoes total thyroidectomy. Genetic testing reveals a RET proto-oncogene mutation at codon 634 (C634F). Which hereditary syndrome is she most likely to carry?
- A MEN1
- B MEN2A ✓
- C MEN2B
- D Familial non-MEN medullary thyroid carcinoma
Correct answer: B. MEN2A
Explanation
RET codon 634 mutations (exon 11) are strongly associated with MEN2A syndrome, which comprises medullary thyroid carcinoma, pheochromocytoma, and primary hyperparathyroidism. Codon 918 mutations characterize MEN2B (which also includes marfanoid habitus and mucosal neuromas). MEN1 involves MENIN gene mutations (chromosome 11q13) and does not include MTC. ATA guidelines classify codon 634 as 'high risk' requiring thyroidectomy by age 5 years in children.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.