A 35-year-old man who has suffered a heart attack has a serum total cholesterol concentration of 500 mg/dL. His father died at 30 years of age from a massive heart attack, and one of his 2 younger siblings also has an increased serum concentration of total cholesterol. This patient most likely has a disorder caused by an autosomal dominant allele affecting which of the following components of cholesterol metabolism?

Question

Quizplus · Accepted Answer

The patient's symptoms and family history suggest familial hypercholesterolemia, which is commonly caused by mutations in the LDL receptor gene, leading to impaired clearance of LDL cholesterol from the bloodstream. This condition is inherited in an autosomal dominant manner. The patient is most likely exhibiting symptoms related to familial hypercholesterolemia (FH). FH is an autosomal dominant inherited disease affecting the LDL receptor gene leading to significant elevation in plasma LDL levels and total cholesterol. Patients who are heterozygous for an FH allele will manifest with total serum cholesterol levels between 300 and 600 mg/dL.

A 35-Year-Old Man Who Has Suffered a Heart Attack Has