A 26-year-old man comes to the office due to skin lesions on his palms. The patient has yellowish skin nodules over the palmar creases that have been increasing in size and number over the past several years. He also has small clusters of yellow papules on his elbows, knees, and buttocks. His father died of a myocardial infarction at age 56. Biopsy of his lesions shows accumulation of lipid-laden macrophages. Immunoblot analysis suggests a lack of ApoE3 and ApoE4 in his circulating lipoproteins. Which of the following is most likely impaired in this patient?

Question

A 26-year-old man comes to the office due to skin lesions on his palms.  The patient has yellowish skin nodules over the palmar creases that have been increasing in size and number over the past several years.  He also has small clusters of yellow papules on his elbows, knees, and buttocks.  His father died of a myocardial infarction at age 56.  Biopsy of his lesions shows accumulation of lipid-laden macrophages.  Immunoblot analysis suggests a lack of ApoE3 and ApoE4 in his circulating lipoproteins.  Which of the following is most likely impaired in this patient?

Quizplus · Accepted Answer

Eductional Objective: Familial dysbetalipoproteinemia (type III hyperlipoproteinemia) is an autosomal recessive disorder characterized by elevated cholesterol and triglyceride levels.  It is caused by defects in ApoE3 and ApoE4, leading to decreased clearance of chylomicrons and VLDL remnants.  Patients can develop eruptive and palmar xanthomas and premature atherosclerosis.

A 26-Year-Old Man Comes to the Office Due to Skin