A 8-yrs-old child has a history since early childhood of malabsorption, ataxia, acanthocytes in the peripheral blood, and very low cholesterol and triglyceride levels. In addition, the patient has been developing progressive, bilateral, concentric contraction of the visual fields and loss of central vision. The underlying pathogenesis of this patient’s disease is
Correct Answer: A defect in the synthesis of apolipoprotein B
Description: The patient has abetalipoproteinemia, which is a rare autosomal recessive disease characterized by an absence of apolipoprotein B. Apolipoprotein B is an integral component of chylomicrons, very-low-density lipoproteins (VLDL), and low-density lipoproteins (LDL). Without the apoprotein, triglyceride and cholesterol cannot be packaged into chylomicrons and VLDL. The disease has its onset in childhood. Malabsorption occurs because dietary fat cannot be packaged into chylomicrons, and intestinal cells fill with lipid. This blocks the reabsorption of fat and other nutrients. Loss of essential fatty acids results in membrane abnormalities in red blood cells with production of acanthocytes (thorny-appearing cells). Neurologic findings, including ataxia, nystagmus, and sensory abnormalities, also occur..
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now