Lipid storage disease: Part III. Ultrastructural evaluation of cultured fibroblasts in sphingolipidoses.

For the purpose of evaluating electron microscopy of tissue culture in making the diagnosis of sphingolipidoses, an ultrastructural study was made on the cultured fibroblasts from 23 patients with the disorders. The characteristic cytoplasmic inclusions were observed in the cultured cells of Fabry disease, Tay-Sachs disease, Sandhoff disease, generalized gangliosidosis, Niemann-Pick disease, metachromatic leukodystrophy, and multiple sulfatase deficiency, and differ in fine structure with these diseases. All these cytoplasmic inclusions were surrounded by a single limiting membrane and enzyme cytochemically showed acid phosphatase activity, indicating their lysosomal origin. Ultrastructurally, the cytoplasmic inclusions showed pleomorphic osmiophilic inclusions in Fabry disease, membranous cytoplasmic bodies (MCB) in Tay-Sachs disease and Sandhoff disease, MCB and vacuolar inclusions containing finely reticulogranular materials in generalized gangliosidosis, myelin-like inclusions in Niemann-Pick disease, concentric lamellar inclusions in metachromatic leukodystrophy, and polymorphic cytoplasmic inclusions in multiple sulfatase deficiency. In the heterozygous carriers of Fabry disease, pleomorphic osmiophilic inclusions were also detected. However, any specific inclusions were not detectable in the cultured fibroblasts of Gaucher disease and Krabbe disease. Availability of electron microscopy in the cultured fibroblasts of sphingolipidoses is discussed.