Long-term effects of bone marrow transplantation for inborn errors of metabolism: A study of four patients with lysosomal storage diseases

Long-term effects of bone marrow transplantation (BMT) were evaluated in patients with I-cell disease, metachromatic leukodystrophy (MLD), Maroteaux-Lamy syndrome or Hunter syndrome (mild form). Donors were human leukocyte antigen (HLA)-matched siblings, and the follow-up periods were 24–71 months after BMT. The enzyme activities were increased in leukocytes, plasma or liver tissues compared with pre-BMT levels. A patient with I-cell disease acquired development of 4–8 month old infants and showed no further progression in cardiac dysfunctions. A patient with MLD showed a decelerated disease progression and an improved peripheral neuropathy, but progressive brain atrophy was not prevented. Patients with Maroteaux-Lamy syndrome or Hunter syndrome showed improvements in hepatomegaly, joint contractures, short stature and tight skin, and this greatly increased their quality of life. These results indicated that the long-term therapeutic effects achieved by BMT were subject to multiple factors including biochemical improvements, a reversibility of affected tissues, or advanced states of disease and central nervous system impairments in inborn errors of metabolism.