Mucopolysaccharidosis Type II Natural History
Mucopolysaccharidosis Type II Natural History
Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is caused by a
 deficiency of iduronate-2-sulfatase (IDS) leading to an accumulation of glycosaminoglycans
 (GAGs) in tissues of MPS II patients, resulting in characteristic storage lesions and diverse
 disease sequelae, and in patients with the more severe form of the disease, irreversible
 neurocognitive decline and higher morbidity and mortality than in patients with the
 attenuated form of the disease.

 There is currently limited information on the natural history of MPS II, especially with
 respect to neurocognitive decline in patients with the more severe form of the disease. This
 study is planned to be an observational medical records review study (data collected
 retrospectively and no investigational product treatment or procedures) in subjects with the
 severe form of MPS II. Collectively, the data may inform the design of future MPS II gene
 therapy treatment studies and may be utilized as historical comparative control data.
Inclusion Criteria:

 1. Documented diagnosis of MPS II confirmed by enzyme activity as measured in plasma,
 fibroblasts, or leukocytes

 2. The subject has at least one of the neurocognitive assessments listed below, which
 occurred prior to age 6 and in or after 2006 in their medical records.

 1. Bayley Scales of Infant and Toddler Development (BSID), any version

 2. Differential Ability Scale (DAS), any version

 3. Griffiths Mental Development Scale (GMDS), any version

 4. Kaufman Assessment Battery for Children (KABC), any version

 5. Kinder Infant Development Scale (KIDS)

 6. Kyoto Scale of Psychological Development (KSPD), any version

 7. Leiter International Performance Scale (LIPS), any version

 8. Mullen Scales of Early Learning (MSEL), any version

 9. Vineland Adaptive Behavior Scales (VABS), any version

 10. Wechsler Intelligence Scale for Children (WISC), any version

 11. Wechsler Preschool and Primary Scale of Intelligence (WPPSI), any version

 3. If the subject has undergone hematopoietic stem cell transplantation (HSCT), they must
 have at least one neurocognitive assessment prior to HSCT.