title: Enzyme-replacement therapy in mucopolysaccharidosis I.
abstract: BACKGROUND
  Mucopolysaccharidosis I is a lysosomal storage disease caused by a deficiency of the enzyme alpha-L-iduronidase. We evaluated the effect of enzyme-replacement therapy with recombinant human alpha-L-iduronidase in patients with this disorder.
  
  
  METHODS
  We treated 10 patients with mucopolysaccharidosis I (age, 5 to 22 years) with recombinant human alpha-L-iduronidase at a dose of 125,000 U per kilogram of body weight given intravenously once weekly for 52 weeks. The patients were evaluated at base line and at 6, 12, 26, and 52 weeks by detailed clinical examinations, magnetic resonance imaging of the abdomen and brain, echocardiography, range-of-motion measurements, polysomnography, clinical laboratory evaluations, measurements of leukocyte alpha-L-iduronidase activity, and urinary glycosaminoglycan excretion.
  
  
  RESULTS
  Hepatosplenomegaly decreased significantly in all patients, and the size of the liver was normal for body weight and age in eight patients by 26 weeks. The rate of growth in height and weight increased by a mean of 85 and 131 percent, respectively, in the six prepubertal patients. The mean maximal range of motion of shoulder flexion and elbow extension increased significantly. The number of episodes of apnea and hypopnea during sleep decreased 61 percent. New York Heart Association functional class improved by one or two classes in all patients. Urinary glycosaminoglycan excretion decreased after 3 to 4 weeks of treatment; the mean reduction was 63 percent of base-line values. Five patients had transient urticaria during infusions. Serum antibodies to alpha-L-iduronidase were detected in four patients.
  
  
  CONCLUSIONS
  In patients with mucopolysaccharidosis I, treatment with recombinant human alpha-L-iduronidase reduces lysosomal storage in the liver and ameliorates some clinical manifestations of the disease.
authors.affiliation: Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, Calif, USA. ekakkis@biomarinpharm.com
authors.forename: E D
authors.initials: ED
authors.lastname: Kakkis
authors.forename: J
authors.initials: J
authors.lastname: Muenzer
authors.forename: G E
authors.initials: GE
authors.lastname: Tiller
authors.forename: L
authors.initials: L
authors.lastname: Waber
authors.forename: J
authors.initials: J
authors.lastname: Belmont
authors.forename: M
authors.initials: M
authors.lastname: Passage
authors.forename: B
authors.initials: B
authors.lastname: Izykowski
authors.forename: J
authors.initials: J
authors.lastname: Phillips
authors.forename: R
authors.initials: R
authors.lastname: Doroshow
authors.forename: I
authors.initials: I
authors.lastname: Walot
authors.forename: R
authors.initials: R
authors.lastname: Hoft
authors.forename: E F
authors.initials: EF
authors.lastname: Neufeld
mesh_terms: D000293:Adolescent; D000328:Adult; D001049:Apnea / Q000188:drug therapy / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D003318:Corneal Opacity / Q000188:drug therapy / Q000209:etiology; D017079:Exercise Tolerance / Q000187:drug effects; D005260:Female; D006128:Growth / Q000187:drug effects; D006529:Hepatomegaly / Q000188:drug therapy / Q000209:etiology; D006801:Humans; D007068:Iduronidase / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D007262:Infusions, Intravenous; D008297:Male; D008059:Mucopolysaccharidosis I / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D016059:Range of Motion, Articular / Q000187:drug effects; D013163:Splenomegaly / Q000188:drug therapy / Q000209:etiology
chemical_list: D007068:Iduronidase