A 7-year-old boy presents with growth retardation, chronic diarrhea, and steatorrhea. Vital signs show weight 15th percentile for age. Laboratory studies reveal fat-soluble vitamin deficiencies (vitamins A, D, E, K), with serum cholesterol of 85 mg/dL. Peripheral blood smear demonstrates acanthocytes. Abdominal imaging shows no biliary obstruction. DNA sequencing identifies mutations in the APOB gene causing premature termination codons. Which lipoprotein cannot be adequately secreted from hepatocytes in this patient?
- A)LDL particles only due to defective LDL receptor ligand binding
- B)Chylomicrons and VLDL due to defective apolipoprotein B-48
- C)HDL particles due to impaired apolipoprotein A-I synthesis
- D)VLDL and LDL due to defective apolipoprotein B-100GABARITO
- E)All lipoproteins equally due to generalized lipid trafficking defect
Explicação
Abetalipoproteinemia results from mutations in APOB or MTP genes. APOB mutations produce non-functional apoB-100, preventing VLDL secretion from liver. ApoB-48 (from enterocytes) is also affected by certain mutations, causing absent chylomicrons. Hepatic VLDL/... Ver explicação completa e trilha adaptativa →