A 52-year-old Indian male presents to the cardiology clinic with a history of premature coronary artery disease (CAD) diagnosed 2 years ago. He is currently on atorvastatin 40 mg daily but his lipid profile remains suboptimal: total cholesterol 280 mg/dL, LDL-C 180 mg/dL, HDL-C 35 mg/dL, triglycerides 320 mg/dL. His liver function tests and creatine kinase are normal. On further questioning, he reports that his father had an MI at age 48 and his brother has familial hypercholesterolemia. The patient is compliant with medication and follows a low-fat diet. Which of the following mechanisms best explains the inadequate response to statin therapy in this patient?