RESUMEN
OBJECTIVE: To describe the perceptions of patients, their caregivers, and their healthcare providers to the development of a new specific instrument for assessment of the quality of life (QoL) in patients with mucopolysaccharidoses (MPS) using a qualitative focus group (FG) design. FGs were held in two Brazilian states (Rio Grande do Sul and Rio de Janeiro). RESULTS: Three versions of the new instrument were developed, each for a different age group: children (age 8-12 years), adolescents (age 13-17), and adults (age ≥ 18). The FGs mostly confirmed the relevance of items. All FGs unanimously agreed on the facets: School, Happiness, Life Prospects, Religiosity, Pain, Continuity of Treatment, Trust in Treatment, Relationship with Family, Relationship with Healthcare Providers, Acceptance, and Meaning of Life. The overall concept of QoL (as proposed by the WHO-World Health Organization) and its facets apply to this patient population. However, other specific facets-particularly concerning clinical manifestations and the reality of the disease-were suggested, confirming the need for the development of a specific QoL instrument for MPS.