The Mucopolysaccharidoses (MPS) are a family of genetic metabolic disorders, caused by specific enzyme deficiencies which result in accumulation of partially degraded glycosaminoglycans (GAGs) within various tissues. As GAGs are common in the body a number of different organ systems can be affected. Involvement of the upper and lower respiratory tract in MPS Type II results in significant airway compromise, with progressive airway obstruction being responsible for a significant proportion of the morbidity and mortality associated with this condition. Hearing loss is a universal finding in MPS, with a third of patients suffering with severe profound hearing loss. There is an unmet need for strong clinical evidence to guide treatment of head, neck and respiratory disease in MPS disorders. A Core Outcome Set (COS) describes the minimum outcome data that should be measured in a clinical study for a particular condition. The lack of an agreed COS for MPS II in general, and specifically head, neck and respiratory disease, makes comparison between studies difficult. There is also a lack of information detailing patient and parent perspectives on the MPS disorders. The ideal COS for head, neck and respiratory disease associated with MPS II would combine both patient/parent and clinician opinion and could be used in the design of all subsequent clinical studies. Following literature review the investigators have created a list of outcomes previously reported for qualitative and quantitative studies investigating head, neck and respiratory disease in MPS II. For the proposed research the investigators will seek opinions of patients, parents, clinicians and scientists to rate these outcomes via the Delphi method. Outcomes scored highest by patients, parents, clinicians and scientists will form a COS for head, neck and respiratory disease in MPS II. The development of a COS can help limit variability outcomes in studies investigating different interventions in MPS II.

Inclusion criteria:

• Confirmed MPS II diagnosis.
• Aged between 12 and 25 years old.
• Parents/ main care givers of child with MPS Type II.
• Adults aged 18 or over.
• Clinicians responsible for direct care and management of at least 2 pediatric MPS Type II patients in the last 12 months.
• Scientists who have worked with MPS Type II within the last 5 years

Exclusion criteria:

• Unconfirmed MPS Type II diagnosis.
• Aged below 12 and above 25 years old.
• Not directly involved in a day to day care.
• Clinicians who only occasionally look after pediatric MPS Type II patients.
• Scientists who have not worked with MPS Type II within the last 5 years

Patients and parents, clinicians and scientists