Galactosylceramide beta-galactosidase and
lactosylceramide beta-galactosidase activities were investigated in normal human brain, leu-kocytes and amniotic fluid cells. The enzymatic assays were performed on brains from 11 patients with
Krabbe's disease, on leukocytes from 16 patients and 18 obligate heterozygotes, and on amniotic fluid cells from 9 foetuses at risk. The brain
enzyme was solubilized from a 900 g-100000 g pellet. With this
enzyme preparation a profound deficiency of
galactosylceramide beta-galactosidase activity in brain, approximately 1% of that in age-matched controls was shown. The
lactosylceramide beta-galactosidase activity of brain was also strongly reduced, but not to the same extent as the other
beta-galactosidase.
Galactosylceramide beta-galactosidase activity in leukocytes from patients with
Krabbe's disease was generally less than 5% of that in age-matched controls and there was no overlap between the patients and the obligate heterozygotes. Carrier detection by the leukocyte
enzyme was, however, not possible because of considerable overlap between heterozygotes and normal controls. The
lactosylceramide beta-galactosidase activity was only moderately reduced in leukocytes, but strongly reduced in cerebral tissue from patients with
Krabbe's disease. The changes in the
glycolipid pattern of cerebral tissue, recently described by us in patients with
Krabbe's disease, offers an explanation to the serious
glycolipid beta-galactosidase deficiency in CNS.