NIEMANN-PICK disease is characterized by the accumulation of sphingomyelin in the reticuloendothelial system of the liver, spleen, bone marrow, and lymph nodes. Alterations in the brain are variable and range from no involvement to a picture of a diffuse neuronal storage disease. Over the last ten years it has become evident that Niemann-Pick disease does not represent a single clinical and biochemical entity, but that there may at least be four conditions in which there is tissue storage of sphingomyelin.1-3 About 85% of patients fall into group A1(classic Niemann-Pick disease) characterized by the onset of hepatosplenomegaly during the first year of life, intellectual deterioration, and the frequent presence of retinal cherry-red spots. Death usually occurs prior to 3 years of age. The essential pathological changes in this condition are the massive and generalized deposition of foam cells, and the presence of ballooned ganglion cells in various