Lynch syndrome (HNPCC) is caused by germline mutations in mismatch repair (MMR) genes. Which gene mutation is associated with the Muir-Torre variant that includes sebaceous skin tumours and keratoacanthomas?
- A MLH1
- B PMS2
- C MSH2 ✓
- D MSH6
Correct answer: C. MSH2
Explanation
Muir-Torre syndrome is a variant of Lynch syndrome specifically associated with germline mutations in MSH2 (and less commonly MLH1), presenting with sebaceous gland tumours (sebaceous adenoma, epithelioma, carcinoma) and keratoacanthomas in addition to MMR-associated visceral malignancies. MSH6 mutations cause Lynch syndrome with a predilection for endometrial and urinary tract cancers. PMS2 mutations cause constitutional mismatch repair deficiency when biallelic.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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