A 20-year-old woman with Hirschsprung disease presents with acute leg pain. The patient had a glioma resected 3 years ago. An X-ray film of the leg reveals a fracture of the left tibia. Laboratory studies show elevated serum levels of calcium and PTH. A CT scan of the patient’s neck demonstrates a solitary parathyroid mass. Two years later, the patient presents with hypeension, and a CT scan of the abdomen displays a 4-cm mass in the right adrenal. Genetic studies conducted on this patient would likely reveal germline mutations in which of the following protooncogenes?
A 20-year-old woman with Hirschsprung disease presents with acute leg pain. The patient had a glioma resected 3 years ago. An X-ray film of the leg reveals a fracture of the left tibia. Laboratory studies show elevated serum levels of calcium and PTH. A CT scan of the patient’s neck demonstrates a solitary parathyroid mass. Two years later, the patient presents with hypeension, and a CT scan of the abdomen displays a 4-cm mass in the right adrenal. Genetic studies conducted on this patient would likely reveal germline mutations in which of the following protooncogenes?
💡 Explanation
**Core Concept**
The patient's presentation suggests a syndrome with multiple endocrine neoplasias, given the presence of a parathyroid mass, an adrenal mass, and previous glioma resection, alongside other symptoms. This scenario points towards a genetic predisposition to develop tumors in multiple endocrine glands.
**Why the Correct Answer is Right**
The clinical presentation of this patient, including Hirschsprung disease, a history of glioma, parathyroid mass, and an adrenal mass, is highly suggestive of **Multiple Endocrine Neoplasia Type 2B (MEN2B)**. MEN2B is characterized by the development of medullary thyroid carcinoma, pheochromocytoma (which could explain the adrenal mass and hypertension), and other features like marfanoid habitus and mucosal neuromas, but not typically the combination seen here without thyroid involvement mentioned. However, given the combination of Hirschsprung disease and the other findings, the condition that best fits the description of multiple tumors and Hirschsprung disease is associated with mutations in the **RET protooncogene**.
**Why Each Wrong Option is Incorrect**
**Option A:** Without specific details on the options provided, we can infer that any option not involving the RET protooncogene would be incorrect given the context of MEN2B and the involvement of Hirschsprung disease, which is associated with RET mutations.
**Option B:** Similarly, this option would be incorrect if it does not involve the RET protooncogene.
**Option C:** This would also be incorrect for the same reasons as above.
**Option D:** If this is not the RET protooncogene, it would be an incorrect choice.
**Clinical Pearl / High-Yield Fact**
The **RET protooncogene** is crucial in the development of certain neural crest-derived tissues, and mutations in this gene are associated with MEN2A, MEN2B, and familial medullary thyroid carcinoma, as well as Hirschsprung disease. Recognizing the pattern of multiple endocrine tumors and other specific clinical features can help in diagnosing these genetic conditions.
**Correct Answer:** D. RET protooncogene
✓ Correct Answer: C. RET
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