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
A degenerative disease involving the cerebellum A defect in the synthesis of apolipoprotein B Degeneration of the posterior columns, spinocerebellar tracts, and coicospinal tracts An absence of high-density lipoproteins