A patient with a history of recurring attacks of pancreatitis, eruptive xanthomas, and increased plasma triglyceride levels (2,000 mg/dL). Which of the following is the most likely deficiency:
## **Core Concept**
The patient's symptoms of recurring pancreatitis, eruptive xanthomas, and significantly elevated plasma triglyceride levels point towards a disorder of lipid metabolism. Specifically, this presentation is suggestive of **hypertriglyceridemia**, which can lead to **pancreatitis** and **cutaneous manifestations** like eruptive xanthomas. The underlying cause is often related to deficiencies in enzymes involved in triglyceride metabolism.
## **Why the Correct Answer is Right**
The correct answer, **Lipoprotein Lipase (LPL)**, is an enzyme crucial for the hydrolysis of triglycerides within lipoproteins, such as very-low-density lipoproteins (VLDL) and chylomicrons, into free fatty acids and glycerol for utilization by tissues. A deficiency in LPL leads to **familial hypertriglyceridemia** or **hyperlipoproteinemia type I**, characterized by elevated levels of chylomicrons, very high plasma triglyceride levels, and the clinical manifestations observed in the patient.
## **Why Each Wrong Option is Incorrect**
- **Option A:** While Apo C-II is an activator of LPL, its deficiency would also lead to hypertriglyceridemia. However, the direct enzyme deficiency leading to this presentation is more specifically related to LPL itself.
- **Option B:** A deficiency in **Apolipoprotein C-III (Apo C-III)** would actually lead to decreased triglyceride levels due to Apo C-III's role as an inhibitor of LPL. Thus, it's not associated with hypertriglyceridemia.
- **Option D:** **CETP (Cholesteryl Ester Transfer Protein)** plays a role in the exchange of cholesteryl esters and triglycerides between lipoproteins. Deficiency or inhibition of CETP increases HDL and decreases LDL and triglycerides, which doesn't match the patient's presentation.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **eruptive xanthomas** are strongly associated with **hypertriglyceridemia**. These skin lesions are small, yellowish papules that appear on the buttocks, thighs, and other areas. They are a classic sign of very high triglyceride levels and can be a clue to underlying disorders of lipid metabolism.
## **Correct Answer: .**