Genetic testing for Parkinson disease: current practice, knowledge, and attitudes among US and Canadian movement disorders specialists

Abstract

Purpose: Genetic testing for Parkinson disease (PD) has not been widely used in clinical practice. In preparation for upcoming precision medicine-designed clinical trials for GBA and LRRK2, we evaluated movement disorders specialists' current practice, knowledge, attitudes, and barriers to genetic testing in PD.

Methods: An anonymous questionnaire was sent to movement disorders specialists at 146 Parkinson Study Group (PSG) sites in the United States (n = 131) and Canada (n = 15) to assess their knowledge and attitudes about genetic testing for PD.

Results: One hundred seventy-eight (47.6%) PSG clinicians completed the questionnaire. Forty-one percent of respondents had not referred any PD patients for genetic testing in the last year and >80% reported referring fewer than 11 patients over the same period. Most common reasons for not referring for genetic testing included lack of insurance coverage/cost to the patient and lack of perceived utility. On a scale of 0-100, the mean level of comfort in respondents' own ability to genetically counsel PD patients on GBA and LRRK2 was 52 (SD = 28). Sixty percent of clinicians correctly answered all questions about the inheritance and penetrance of GBA and LRRK2 variants.

Conclusions: There is an urgent need to increase knowledge and reduce practical barriers to genetic counseling and testing in PD.

Keywords: GBA; LRRK2; Parkinson disease; genetic testing; questionnaire.

Fig. 1

Responses to the question “To what extent do any of the following keep you from ordering genetic tests for patients with Parkinson disease (PD) in your clinic?” Participants graded each option on a scale from 0 to 100. Orange bars represent the mean grade for each response, and horizontal black lines represent the standard deviation. All respondents answered each question separately.

Fig. 2

Responses from 160 participants to questions on PD GENE initiative. For each question participants could answer “yes,” “no,” or “not sure.” After the last question about ethical concerns, participants had an option to elaborate using free text.