OBJECTIVES : Mucopolysaccharidosis II (MPS II; Hunter syndrome) is a rare, progressive lysosomal storage disease that affects multiple organs. This study aimed to characterize musculoskeletal and cardiac outcomes and associated healthcare resource use in patients with MPS II.

METHODS : Patients with MPS II diagnosed between 1997 and 2017 across 19 US sites were assessed in a retrospective chart review. Clinical characteristics and resource use associated with musculoskeletal and cardiac disease manifestations were summarized for all patients.

RESULTS : Overall, 140 male patients (18 deceased) were included; 108 (77.1%) had received enzyme replacement therapy and 87 (62.1%) had documented cognitive impairment. Musculoskeletal abnormalities were reported for almost all patients (95.0%) and were first documented at a median (range) age of 3.9 (0.2–59.4) years. The most commonly reported musculoskeletal disease manifestations were facial dysmorphism (81.4%) and multiple contractures (81.4%). Decreased mobility was reported in almost half of patients (46.4%). Cardiac abnormalities were recorded for 72.1% of patients and were first documented at a median (range) age of 5.9 (0–26.0) years. The most common cardiac disease manifestation was valvular disease (68.6%), followed by cardiomyopathy (23.6%). Resource utilization (analysis population; n=123) associated with musculoskeletal and cardiac abnormalities was high, including outpatient visits to orthopaedic surgeons and cardiologists for 65.9% and 74.0% of patients, respectively. Almost all patients underwent imaging procedures (87.8%); the most common imaging modality was X-ray (71.5%), followed by magnetic resonance imaging (59.3%), computed tomography (39.8%) and echocardiogram (36.6%). Use of supportive services and medical equipment relevant to musculoskeletal disease manifestations was frequent, most commonly physical therapy (57.7%) and wheelchair use (19.5%).

CONCLUSIONS : Musculoskeletal and cardiac abnormalities are common in patients with MPS II and are associated with a substantial clinical burden and high healthcare resource utilization. Shire, a Takeda company, funded this study and writing support.