A modified Balke Treadmill Test was performed. Briefly, patients began walking at 2.0 mph with a 2% increase in grade every 2 min. A 12-lead electrocardiogram was monitored continuously throughout the test for the determination of heart rate and dysrhythmias or ischemic changes. Heart rate was measured at the end of each stage (i.e. every 2 min) .

Bilateral shoulder flexion, elbow extension, and hip extension were measured using goniometry. Improvements are defined for all joints as >5°.

Cardiac ultrasounds were obtained at baseline and month 24. Two-dimensional imaging was obtained for determination of anatomy. Shortening fraction (SF [normal > 27%]) was calculated by standard methods to determine the normal systolic cardiac function

Pulse-wave and color Doppler interrogation of cardiac valves was performed for determination of valve regurgitation

6 minute walk test (6MWT) was performed to assess overall physical function and health status. In brief, a 30m hospital corridor marked by colored tape at each end was used. Subjects were instructed to walk from end to end at their self-selected pace, while attempting to cover as much distance as possible in the 6 min. The patients were instructed to walk around the mark as they changed direction. The time and distance covered was recorded, as was the heart rate prior to and immediately after completion of the walk test.

To find the association between the rate of change in 6MWT, and anti drug antibody (ADA) titer, a statistical test is performed adjusting for age at the time of enrollment.

Number of participants experiencing severe adverse events that occur after administration with Laronidase to determine the feasibility of giving weekly Laronidase

difference between baseline and month 24 growth velocities

Baseline growth velocity value was available in six of ten participants. One female participant was excluded from the within-group growth analyses due to a bone age of 14.5 years

Handgrip strength is measured three times in both hands with a mechanical handheld Biodex System 3 dynamometer (Biodex medical Systems, Inc., Shirley, NY) with the subject in a seated position at each visit; the average for each hand is presented.

A modified Balke Treadmill Test was performed. Briefly, patients began walking at 2.0 mph with a 2% increase in grade every 2 min. A 12-lead electrocardiogram was monitored continuously throughout the test for the determination of heart rate and dysrhythmias or ischemic changes. Heart rate was measured at the end of each stage (i.e. every 2 min) .

Bilateral shoulder flexion, elbow extension, and hip extension were measured using goniometry. Improvements are defined for all joints as >5°.

Cardiac ultrasounds were obtained at baseline and month 24. Two-dimensional imaging was obtained for determination of anatomy. Shortening fraction (SF [normal > 27%]) was calculated by standard methods to determine the normal systolic cardiac function

two subjects didn't have both baseline and month 24 echo data

Pulse-wave and color Doppler interrogation of cardiac valves was performed for determination of valve regurgitation

Two subjects didn't have both baseline and month 24 echo data

6 minute walk test (6MWT) was performed to assess overall physical function and health status. In brief, a 30m hospital corridor marked by colored tape at each end was used. Subjects were instructed to walk from end to end at their self-selected pace, while attempting to cover as much distance as possible in the 6 min. The patients were instructed to walk around the mark as they changed direction. The time and distance covered was recorded, as was the heart rate prior to and immediately after completion of the walk test.

To find the association between the rate of change in 6MWT, and anti drug antibody (ADA) titer, a statistical test is performed adjusting for age at the time of enrollment.