Study of Long Term Safety and Clinical Outcomes of Idursulfase IT and Elaprase Treatment in Pediatric Participants Who Have Completed Study HGT-HIT-094

Inclusion Criteria:

- Participants must have completed Visit Week 52 assessments in Study HGT-HIT-094
(NCT02055118).

- The participant's parent(s) or legally authorized guardian(s) must have voluntarily
signed an Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved
informed consent form after all relevant aspects of the study have been explained and
discussed. Consent of the participant's parent(s) or legally authorized guardian(s)
and the participant's consent/assent, as relevant, must be obtained.

- The participant has continued to receive Elaprase on a regular basis in Study
HGT-HIT-094 (NCT02055118).

Exclusion Criteria:

- The participant has experienced, in the opinion of the investigator, a safety or
medical issue that contraindicates treatment with idursulfase-IT, including, but not
limited to, uncontrolled seizure disorder, bleeding disorder, and clinically relevant
hypertension.

- The participant has a known hypersensitivity to any of the components of
idursulfase-IT.

- The participant has clinically relevant intracranial hypertension.

- The participant is enrolled in another clinical study, other than HGT-HIT-094
(NCT02055118), that involves clinical investigations or use of any investigational
product (drug or [intrathecal/spinal] device) within 30 days prior to study enrollment
or at any time during the study.

- The participant has any known or suspected hypersensitivity to anesthesia or is
thought to be at an unacceptably high risk for anesthesia due to compromised airways
or other conditions.

- The participant has a condition that is contraindicated as described in the
SOPH-A-PORT® Mini S, Implantable Access Port, Spinal, Mini Unattached, with Guidewire
(SOPH-A-PORT Mini S) intrathecal drug delivery device (IDDD) Instructions for Use,
including:

1. The participant has had, or may have, an allergic reaction to the materials of
construction of the SOPH-A-PORT Mini S device.

2. The participant's body size is too small to support the size of the SOPH-A-PORT
Mini S Access Port, as judged by the investigator.

3. The participant's drug therapy requires substances known to be incompatible with
the materials of construction.

4. The participant has a known or suspected local or general infection.

5. The participant is at risk of abnormal bleeding due to a medical condition or
therapy.

6. The participant has 1 or more spinal abnormalities that could complicate safe
implantation or fixation.

7. The participant has a functioning CSF shunt device.

8. The participant has shown an intolerance to an implanted device.