To the Editor: Watson et al. report performing an allogeneic bone marrow transplantation in a 16-month-old child with Pompé's disease (Feb. 6 issue).1 Because the patient died on day 33 after transplantation, the long-term effects of the procedure could not be evaluated. Despite this, the authors encourage further attempts at treatment of Pompé's disease with bone marrow transplants. Their only argument in favor of this recommendation seems to be that acid maltase, the enzyme that is deficient in Pompé's disease, may be supplied by enzyme-competent bone marrow cells. The authors do not take into account the complicated molecular and cellular., No extract is available for articles shorter than 400 words.