Outcomes after Hematopoietic Cell Transplantation for Hurler Syndrome after Implementation Newborn Screening in US and Europe

Hurler syndrome (HS), the most severe phenotype in the spectrum of Mucopolysaccharidosis type I, is caused by a severe deficiency of the lysosomal enzyme alpha-L-iduronidase (IDUA). HS is clinically characterized by a progressive and ultimately fatal multi-system deterioration with involvement of the central nervous system. At present, hematopoietic cell transplantation (HCT) is the only treatment able to prevent central nervous system deterioration and therefore considered the treatment of choice in HS. In large intercontinental cohorts, predictors for outcomes (short and long-term) were found to be age at HCT and enzyme levels after HCT. Newborn screening (NBS) and early HCT could therefore potentially impact outcomes. In several States in the US and Europe NBS has been implemented over the last couple years. We were interested in the age at HCT and outcome of HS patients diagnosed by NBS.