OBJECTIVES: Approximately 7-10% of Parkinson’s disease (PD) patients carry a GBA mutation (GBA-PD patients), which may influence the clinical course of the disease. This study aimed to explore patients’ experiences of GBA-PD and identify the most relevant and important symptoms and impacts to inform future clinical trial measurement strategies.

METHODS: Twenty individuals with PD (n=15 GBA-PD; n=5 idiopathic-PD) participated in face-to-face, qualitative concept elicitation interviews. The interviews explored concepts spontaneously reported by patients and those identified through a literature review. Telephone interviews with five expert clinicians (neurologists or clinical geneticists) from the US, Israel, and Italy included discussion of a preliminary conceptual model. Verbatim transcripts were thematically analysed using Atlas.ti software.

RESULTS: Thirty symptoms reported by PD patients were categorized as motor, non-motor, and cognitive/psychiatric symptoms. Tremor (n=18), memory loss (n=18), rigidity/stiffness (n=16), and speech problems (n=12) were found to be the most important and impactful symptoms, although a myriad of other symptoms were also highly relevant to the majority of patients. Key impacts reported included: sleep disturbances (n=18), reduced social interaction (n=17), depressed mood (n=14), dyskinesia (n=14), handwriting changes (n=13) and a fear of falling (n=13). Key symptoms and impacts were consistently reported by GBA-PD and idiopathic-PD patients. The clinician interviews supported the patient interview findings, although clinicians indicated that cognitive/psychiatric symptoms may present earlier in the GBA-PD population. The concepts emerging from the research informed updates to a conceptual model of GBA-PD patients’ disease experience originally derived from the literature.

CONCLUSIONS: The findings provide an in-depth understanding of the participant experience of GBA-PD and the impacts it has on health-related quality of life. The findings confirm that the concepts relevant to assess in GBA-PD patients are consistent with those relevant to assess in idiopathic-PD patients; however, slightly more consideration of cognitive/psychiatric symptoms may be warranted in GBA-PD populations.