Safety and Dose Ranging Study of Human Insulin Receptor MAb-IDUA Fusion Protein in Adults and Children With MPS I

Inclusion Criteria: * Written consent and assent as required * Diagnosis of MPS 1 confirmed by clinical signs and symptoms, documented fibroblast or leukocyte IDUA enzyme activity of less than 10% the lower limit of normal * Female patients must not be pregnant, willing to utilize appropriate birth control methods and undergo pregnancy testing during the study * if taking standard ERT, must be willing to discontinue for 1 week prior to dosing and for the study duration Additional Inclusion Criteria, Stage 1: * 18 years of age or older * must have a diagnosis of Hurler-Scheie or Scheie syndrome Additional Inclusion Criteria, Stage 2: * 2 years of age or older (and less than 18) * must be willing to undergo CNS testing, including assessment of CSF via lumbar puncture, MRI scans and neurocognitive testing * must have evidence of Hurler-Scheie or Scheie with CNS involvement, as evidence by: * score of 1 to 3 standard deviations below mean on IQ testing (i.e. IQ=55 or more) or in one domain of neuropsychological function (language, memory, non-verbal ability) OR * documented historical evidence of a decline greater than 1 standard deviation on sequential testing, OR * score between 0.75 and 1 standard deviation below the mean, AND cognitive deficit affects daily performance Exclusion Criteria: * Refusal to complete all assessments * Pregnant or Lactating * Received investigational drug within 1 year prior to study enrollment * Medical condition or extenuating circumstance t…