A 19-year-old presents with mucocutaneous pigmentation of the lips and buccal mucosa, recurrent colicky abdominal pain from intussusception, and multiple polyps throughout the gastrointestinal tract on endoscopy. Biopsy shows arborizing smooth muscle cores within the polyps. Which germline mutation underlies this condition?
- A STK11 ✓
- B BMPR1A
- C PTEN
- D MUTYH
Correct answer: A. STK11
Explanation
Peutz-Jeghers syndrome results from a germline mutation in STK11 (LKB1), a serine-threonine kinase tumour suppressor. Its hamartomatous polyps characteristically show arborizing strands of smooth muscle, and patients carry elevated lifetime risks of gastrointestinal, pancreatic, breast, and gynaecological malignancies. BMPR1A and PTEN are linked to juvenile polyposis and Cowden syndrome respectively, while MUTYH causes recessive polyposis with adenomatous, not hamartomatous, polyps.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.