A 19-year-old woman has Cushing syndrome with low ACTH, multiple small bilateral adrenal nodules, spotty skin pigmentation on the lips and conjunctiva, cardiac myxoma, and acromegaly from a growth hormone-producing pituitary adenoma. Germline testing would most likely reveal a mutation in:

• A MEN1 gene encoding menin
• B PRKAR1A gene encoding protein kinase A regulatory subunit 1-alpha ✓
• C GNAS gene encoding the alpha subunit of Gs protein
• D RET proto-oncogene

Explanation

Carney complex comprises primary pigmented nodular adrenocortical disease, lentigines, cardiac and cutaneous myxomas, and pituitary, testicular, or thyroid tumors, caused by germline PRKAR1A mutations. MEN1 does not include myxomas or lentigines. Somatic GNAS mutations define McCune-Albright syndrome, which features polyostotic fibrous dysplasia and cafe-au-lait spots rather than myxomas. RET mutations cause MEN2 with medullary thyroid carcinoma and pheochromocytoma.

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.