Potential efficacy of enzyme replacement and substrate reduction therapy in three siblings with Gaucher disease type III.

We report three siblings with Gaucher disease type III, born between 1992 and 2004. During this period, new developments resulted in different potential therapies, changing clinical practice. The two eldest siblings received enzyme replacement therapy (ERT) from the age of 24 and 5 months respectively, later followed by an increase in dosage. ERT was combined with substrate reduction therapy (SRT) from the ages of 12 and 8 years, respectively. In the youngest sibling the combination of high-dose ERT and SRT was given from the age of 5 months. The two eldest siblings showed significant neurological impairment from the age of 1.5 years, starting with a convergent strabismus and partial oculomotor apraxia, followed by cognitive decline and an abnormal EEG and BAER. In contrast, the neurological development in the youngest sibling is almost completely normal. At the age of 3 years, cognitive development, EEG and BAER are all normal. Disturbed saccadic eye movements, which were already present at the start of therapy, remained stable. In addition to the clinical efficacy, we report on the biochemical response to therapy. Based on our results, the combination of high-dose ERT and SRT should be considered as a possible therapeutic approach for GD III, especially if started at a young age. Further follow-up studies are necessary to explore the long-term therapeutic effects.

Restricted upper extremity range of motion in mucopolysaccharidosis type I: no response to one year of enzyme replacement therapy.

BACKGROUND: Mucopolysaccharidosis type I (MPS I) results from deficiency of the lysosomal enzyme alpha-L: -iduronidase (IDUA). Glycosaminoglycans (GAGs) accumulate in multiple organs and the storage in connective tissues results in restricted mobility. Previous studies provided evidence of an improvement in range of motion (ROM), as measured by goniometry, after supplementation of recombinant enzyme (ERT). AIM: The aim of the study was to evaluate the efficacy of ERT in improving ROM in patients with MPS I, using a blinded three-dimensional (3D) video analysis of unrestricted movements of the upper extremities. METHODS: In 6 patients with the attenuated phenotype of MPS I, the longitudinal changes in the upper extremity ROM were analysed by 3D video analysis during one year of ERT. RESULTS: At baseline, all studied movements except for elbow flexion were restricted. No significant improvement of the restricted upper extremity ROM was observed after one year of ERT. CONCLUSION: Long-standing restrictions in ROM probably cannot be reversed by ERT. Early initiation of treatment might be essential to prevent irreversible functional defects.

Home treatment with enzyme replacement therapy for mucopolysaccharidosis type I is feasible and safe.

OBJECTIVE: Intravenous enzyme replacement therapy (ERT) with recombinant alpha-L-iduronidase may ameliorate the non-neurological symptoms in patients with mucopolysaccharidosis type I (MPS I). Since home-based ERT for Gaucher and Fabry diseases has been reported to be safe and successful, we investigated the feasibility and safety of home therapy in patients with MPS I. SETTING: This two-centre study included 17 ERT-treated MPS I patients between 1 and 35 years of age. A patient was allowed to transfer to home treatment after a minimum period of 6 months of in-hospital administration of ERT and after a self- or home nurse-supported home setting was arranged. RESULTS: Thirteen out of 17 patients transferred to home treatment with a median time to transfer of 13 months (range 7-40 months). Two patients preferred to continue ERT in the hospital, whereas for two other patients the transfer to home was hampered for practical reasons. All patients who received ERT at home were assisted by either a relative or a nurse. In total over 1000 home infusions were performed and no serious complications were observed. Two infusion-associated reactions were observed, both within the first 3 months of in-hospital administration of ERT. All patients except one developed antibodies against the recombinant enzyme, but this was not associated with the development of hypersensitivity reactions. CONCLUSION: ERT for MPS I applied at home is safe and might alleviate the burden of life-long intravenous treatment in these patients.

Haematopoietic cell transplantation (HCT) in combination with enzyme replacement therapy (ERT) in patients with Hurler syndrome.

Hurler syndrome (MPS 1H) is the severe form of mucopolysaccharidosis type 1 (MPS 1). Haematopoietic cell transplantation (HCT) is the treatment of choice, but carries a high incidence of graft failure and morbidity. The use of enzyme replacement therapy (ERT) might improve the clinical signs and symptoms before HCT, resulting in less transplantation-related complications. Moreover, clearance of glycosaminoglycans (GAG's) from the bone marrow might improve engraftment. Twenty-two patients with MPS 1H received one or more HCT procedures in combination with ERT. One patient with severe cardiomyopathy improved significantly after ERT. All children were in a relatively good clinical condition before HCT. Of patients 59, 82 and 86% were alive and engrafted after one, two and three HCT procedures, respectively. Two patients died after repetitive HCT. No serious ERT-infusion-related toxicity occurred. ERT with HCT was well tolerated. Neither a positive nor a negative effect on the number of patients who are alive and engrafted after receiving ERT before HCT as compared to a historic cohort was noted. However, patients in a poor clinical condition before HCT might benefit from ERT.

Plasma chitotriosidase in male Fabry patients: a marker for monitoring lipid-laden macrophages and their correction by enzyme replacement therapy.

Increased plasma chitotriosidase is a well established surrogate marker for the occurrence of lipid-laden macrophages in the glycosphingolipidosis Gaucher disease. The complete lack of surrogate markers for Fabry disease, X-linked globotriaosylceramidosis stemming from deficiency in the lysosomal alpha-galactosidase A (AGA), prompted us to study chitotriosidase in this disorder. In male Fabry patients plasma chitotriosidase is significantly elevated, consistent with the presence of lipid-laden macrophages in several tissues. Increased levels are detectable at very young age and precede clinical manifestations. No strict correlation exists with severity of disease manifestations. Upon therapy with either of the two available recombinant AGA preparations, plasma chitotriosidase levels are nicely normalized in male Fabry patients. However, in patients developing neutralizing antibodies towards AGA, reduction in plasma chitotriosidase is hampered. In sharp contrast to the situation in male patients, females heterozygous for AGA deficiency show no significantly elevated plasma chitotriosidase. This suggests that circulating endogenous AGA in heterozygotes is sufficient to supplement enzyme-deficient macrophages. In conclusion, for the first time a biological marker for lipid-laden cells in Fabry patients is demonstrated; elevated plasma chitotriosidase levels reflecting lipid-laden macrophages. Corrections in this marker illustrate the efficacy of enzyme replacement therapy in clearing the lipid accumulation in this particular cell type.