After a herculean data-gathering effort, in this issue of Blood, Aldenhoven and colleagues from Europe and North America provide an eye-opening assessment of long-term neurocognitive, organ, joint, and tissue function after allogeneic transplantation of children with mucopolysaccharidosis type I–Hurler syndrome (MPS-IH), along with an analysis defining a path to better these outcomes.

BACKGROUND Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disease subdivided into three phenotypes of increasing severity: Scheie, Hurler-Scheie and Hurler. To gauge the effectiveness of treatments and to determine the load likely to fall on health-care systems, it is necessary to understand the prevalence and natural progression of the disease especially with regard to life-e...

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder characterised by the deficient activity of iduronidase and by the presence of MPS vacuoles in many tissues of affected patients. We studied whether these characteristics could be used for the antenatal diagnosis of the disease. We obtained amniotic fluid cells from two pregnancies at risk for MPS I, one pregnancy at risk for G...

Enzyme replacement therapy (ERT) for the lysosomal storage disease mucopolysaccharidosis I (MPS I) involves i.v. injection of alpha-l-iduronidase, which can be taken up by cells throughout the body. While a significant immune response to ERT has been shown in patients with MPS I, little is known about what effect anti-enzyme antibodies have on treatment efficacy. In this issue of the JCI, Dicks...