Membranous cytoplasmic bodies

The deficiency in hexosaminidase A and B occurring in Sandhoff disease results in accumulation of GM2 and GA2 primarily in the lysosomes of neuronal cells (Fig. 17.3), leading to the formation of membranous cytoplasmic bodies (MCBs) (Tutor, 2004). 

The typical ultrastructural ganglion cell abnormalities consist of membranous cytoplasmic bodies (MCB) (see fig. 3) which are round or oval, measure 0.5 to 2.0// in diameter and may occupy a considerable portion of the cytoplasm (Terry and Weiss 1963, Korey et al. 1963a, b, Samuels et al. 1962, 1963, 1965, Terry and Korey 1960, 1963). They are also found in the axis cylinders, glial cells and perivascular cells. Their composition and pathogenesis is discussed in detail below. Other intracellular components appear diminished in number. Vacuoles and small channels may be seen which impinge on the Golgi apparatus. The mitochondria appear normal, even in highly abnormal cells, and ribosomes are plentiful. 

Samuels, S., N. K. Gonatas, and M. Weiss Formation of the membranous cytoplasmic bodies in Tay-Sachs disease an in vitro study. J. Neuropath, exp. Neurol. 24, 256 (1965). 

Studies in Tay-Sachs disease. V. The membrane of the membranous cytoplasmic body. 

Tallman, J. F., Jr., Brady, R. O., and Suzuki, K., 1971, Enzymic activities associated with membranous cytoplasmic bodies and isolated brain lysosomes, /. Neurochem. 18 1775-1777. 

FIGURE 2. An electron micrograph of a typical neuronal cell from the brain of a patient with type I Gm2-gangliosidosis. Numerous membranous cytoplasmic bodies (MCB) may be seen in the cytoplasm. From Terry and Weiss, 1963. 

FIGURE 3. Typical isolated membranous cytoplasmic bodies (MCB). Magnification X 34,000. From Suzuki et al., 1969. 

Patients with GMi-gangliosidosis have rarefaction of the bones and deformed vertebrae. The neuronal cells in the brain are distended with membranous cytoplasmic bodies which resemble in some degree the inclusions found in nerve cells of Tay-Sachs patients. The spleen and liver are enlarged, and the bone marrow contains foam cells distended with stored material. The glomeruli of the kidneys are also swollen with accumulating substance. 

Samuels, S., Korey, S., Gonatas, J., Terry, R., and Weiss, M., 1963, Studies on Tay-Sachs disease IV. Membranous cytoplasmic bodies, /. Neuropath. Exp. Neurol. 22 81. 

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