Disorders of lipid metabolism

You examine an infant in your office. On exam you observe hypotonia, as well as the findings shown in Figures A and B. You order laboratory testing, which demonstrates the findings shown in Figure C. Which of the following is the most likely pathologic mechanism involved?

An 8-year-old boy presents to his primary care pediatrician for routine check-up. During the visit, his mom says that she has noticed yellow bumps on his eyelids and was concerned about whether they were a problem. Upon hearing this concern, the physician inquires about parental health history and learns that both parents have high cholesterol despite adhering to a statin regimen. Furthermore, other family members have suffered early myocardial infarctions in their 30s. Physical exam reveals flat yellow patches on the patient's eyelids bilaterally as well as hard yellow bumps around the patient's ankles. Based on clinical suspicion an LDL level is obtained and shows a level of 300 mg/dL. What protein is most likely defective in this patient causing these findings?