The effect of haemopoietic stem cell transplantation on the ocular phenotype in mucopolysaccharidosis type I (Hurler).

PURPOSE: To determine whether the ocular phenotype in patients with mucopolysaccharidosis type I (MPSI) Hurler is affected by the efficacy of previous haemopoietic stem cell transplantation (HSCT).

DESIGN: A retrospective cohort study of patients with MPSI who had undergone treatment with HSCT.

METHODS: Ocular phenotype was documented for each patient and compared to levels of biomarkers representing efficacy of previous transplantation.

MAIN OUTCOME MEASURES: Assessment of visual acuity (VA), severity of corneal clouding and the presence of optic neuropathy or retinopathy. Biomarker assessment included dermatan sulphate/chondroitin sulphate (DS/CS) ratio and iduronidase enzyme level.

RESULTS: Severe corneal clouding was significantly greater in patients with lower iduronidase levels (p = 0.023) and raised DS/CS ratio (R2  = 0.28 p = 0.043). Better VA was related to a higher iduronidase levels (R2  = 0.15, p = 0.004) and lower DS/CS ratio (R2  = 0.38, p = 0.001).

CONCLUSION: Improved ocular phenotypes in MPSI are associated with markers signifying efficacy of prior transplant. Early and effective HSCT may result in a better visual prognosis and reduction in ocular complications for patients with MPSI.