Lactosyl ceramidosis: catabolic enzyme defect of glycosphingolipid metabolism.

A 3-year-old Negro female showed clinical evidence of a neurovisceral storage disorder that has been characterized by the specific elevation of lactosyl ceramide in erythrocytes, plasma, bone marrow, urine sediment, liver biopsy, and brain biopsy. A galactosyl hydrolase deficiency was demonstrated by the inability to cleave lactosyl ceramide labeled with tritium in the terminal galactose. The enzyme deficiency may be the primary cause of this previously unreported sphingolipidosis.