Long-term therapeutic efficacy of allogenic bone marrow transplantation in a patient with mucopolysaccharidosis IVA.

Mucopolysaccharidosis IVA (MPS IVA) is one of the lysosomal storage diseases. It is caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase. Deficiency of this enzyme leads to accumulation of the specific glycosaminoglycans keratan sulfate and chondroitin-6-sulfate. This accumulation has a direct impact on cartilage and bone development, resulting in systemic skeletal dysplasia. There is no curative therapy for this skeletal dysplasia. This report describes long-term therapeutic efficacy in a 15-year-old boy with a severe form of MPS IVA who received successful allogeneic bone marrow transplantation (BMT) from his HLA-identical carrier sister. The level of the GALNS enzyme in the recipient's lymphocytes reached almost half of normal level within two years after BMT. For the successive 9+ years post-BMT, GALNS activity in his lymphocytes maintained the same level as the donor's, and the level of urinary uronic acid was reduced. Lumbar bone mineral density increased around 50% one year later post-BMT and was kept consistent. Radiographs showed that the figures of trochanter major and minor appeared, while the epiphyseal dysplasia in the femoral cap was almost unchanged. Loud snoring and apnea disappeared. Vital capacity increased to around 20% for the first two years and was maintained. Activity of daily life (ADL) was improved in work/study efficacy, respiratory status, sleep, joint pain, and frequency of infection. In conclusion, the long-term study of hematopoetic stem cell transplantation has shown clinical improvements in respiratory function, radiograph findings, ADL, and biochemical findings, suggesting that it is a potential therapeutic option for patients with MPS IVA.