Ultrastructural study of biopsy specimens of rectal mucosa. Its use in neuronal storage diseases.

Rectal mucosa biopsy specimens from patients with neuronal storage diseases were examined by electron microscopy. The diseases were Tay-Sachs disease, Sandhoff's disease, Niemann-Pick disease types B and C, late infantile metachromatic leukodystrophy, GM1 gangliosidosis type 1, beta-galactosidase-neuraminidase deficiency, I-cell disease, and mucopolysaccharidoses (Hunter's syndrome and Sanfilippo's syndrome type A). Unmyelinated nerve fibers, endothelial cells, fibroblasts, plasma cells, and histiocytes were seen in the specimens. Except for plasma cells, the results thus obtained for various cells were similar to those obtained from skin and conjunctival biopsy specimens, which have been already reported. There has been no report so far on ultrastructure of the plasma cell in these diseases. Storage materials, eg, dense bodies and membrane-bound vacuoles, were observed in the plasma cells in various storage diseases, with the exception of late infantile metachromatic leukodystrophy. Thus, electron microscopy of rectal mucosa is useful in making diagnoses and examining plasma cells in some neuronal storage diseases.