Late Infantile Metachromatic Leukodystrophy: The Nature of the Chromotrope

In 1910 Alzheimer and Baroncini¹ reported the first case of metachromatic leukodystrophy in an adult, and in 1933 metachromatic leukodystrophy occurring in late infancy was reported by Greenfield.² Since that time efforts have been made by many authors to elucidate the nature of a metachromatic material seen in the white matter of the morbid brain.

Greenfield³ considered the metachromatic material to be a galactolipid on the basis of a positive periodic acid-Schiff (PAS) reaction of this material. However, as is well known, not only the glycolipids, but also polysaccharides, mucopolysaccharides, mucoproteins, glycoproteins, unsaturated fatty acids, and phospholipids are PAS-positive.⁴ Greenfield mentioned in his paper that "this method is not very specific in that it stains many of the more complex lipids such as myelin, and lipochrome, as well as many of the fat granule cells in areas of ischemic softening." In 1954 Feigin⁵ reported a