THE typical ophthalmoscopic picture of a "cherry-red spot" is only one of the pathognomonic elements of infantile amaurotic idiocy, or Tay-Sachs' lipoidotic ganglioside disease (Danis, Begaux, and Decock, 1957). A similar picture was also observed in Niemann-Pick disease (sphingomyelin lipoidosis disease) in about 60 per cent. of cases (Videbaek, 1949) and even in two cases of Gaucher's cerebro...

The pseudodeficiency of lysosomal hydrolases described as a significant reduction in enzyme activi­ty in vitro in clinically healthy individuals, can lead to diagnostic errors in the process of biochemical analysis of lysosomal storage disease in case of its combination with pathology of another origin. Pseudodeficiency is mostly caused by some non-pathogenic changes in the corresponding gene. ...