A 52-year-old Indian man presents to the outpatient clinic with recurrent premature coronary artery disease (CAD). His father died of MI at age 48. On examination, he has xanthomas on his Achilles tendons and corneal arcus. Lipid profile: Total cholesterol 520 mg/dL, LDL-C 450 mg/dL, HDL-C 35 mg/dL, Triglycerides 150 mg/dL. Genetic testing confirms homozygous familial hypercholesterolaemia (FH). Which of the following mechanisms best explains the markedly elevated LDL-C in this patient?