Arylsulfatase A deficiency in bone marrow fibroblasts of two different forms of metachromatic leukodystrophy

Early growth of bone marrow fibroblasts from bone marrow aspirates was accomplished in 30 attempted cases by an improvement in the culturing technique. Bone marrow fibroblasts could be subcultivated before the end of 2 weeks in culture and could be assayed for enzymatic activity in less than 3 weeks. Marked deficiency of arylsulfatase A was demonstrated in cultured bone marrow fibroblasts of 2 documented cases of metachromatic leukodystrophy (AALD). The enzyme activity in bone marrow fibroblasts of a patient with late infantile MLD was 5.9, while in a patient whose disease started at the age of 15, the activity was 27.9 nmoles of 4-nitrocatechol per milligram of protein per hour. The mean activity in the control group was 729.9 ± 159.5. No difference in the levels of arylsulfatase B activity was demonstrated between patients and control subjects. It appears that cultured bone marrow fibroblasts are a useful system for the detection and study of certain inborn errors of metabolism.