Deficiency of monogalactosyl diglycerid beta-B-galactosidase activity in krabbe's disease

Monogalactosyl diglyceride has previously been demonstrated to be intimately associated with brain white matter, especially myelin. Enzymes responsible for its biosynthesis and degradation have been reported to be present in rat and mouse brain. In the present study, the β-galactosidase responsible for the degradation of this brain specific compound was demonstrated to be extremely deficient in brain, liver and skin fibroblasts from patients who died of Krabbe's disease. This deficiency is the third enzymatic block demonstrated in this disorder. The β-galactosidase activity toward galactocerebroside and psychosine is also extremely deficient. This finding provides new information about the substrate recognition pattern of this enzyme and about the possible etiology of globoid cell leukodystrophy.