Psychosocial Factors Involved in Genetic Testing for Rare Diseases: A Scoping Review.

: Rare diseases are predominantly genetic in etiology and characterized by a prolonged 'diagnostic odyssey'. Advances in genetic testing (GT) have helped shorten the time to diagnosis for rare/undiagnosed conditions. We aimed to synthesize the evidence on psychosocial factors related to GT for rare diseases to inform more person-centered approaches to care. : We conducted a systematic literature search in six databases using structured terms (September 2024). Retrieved articles underwent independent dual review. Data were extracted and collated in tables for analysis. Thematic analysis was used to identify promoters/barriers to GT for patients and families. Findings were validated by a patient advocate and were reported using PRISMA-ScR guidelines. Synthesized findings were mapped to the Theory of Planned Behavior to inform intervention development. : Of 1730 retrieved articles, 32 were included for data extraction/synthesis. Studies employed qualitative (n = 19), quantitative (n = 10), and mixed-methods (n = 3) approaches. Nearly all (29/32, 91%) were non-interventional, reporting on decision-making cognitions/processes (19/32, 59%), attitudes/preferences (15/32, 47%), psychosocial impact (6/32, 19%), and knowledge/awareness (4/32, 8%) of pre-conception/prenatal/diagnostic GT and carrier screening. Promoters included understanding GT, ending the diagnostic odyssey, actionable outcomes, personal/family history, altruism, and reproductive decision-making. Barriers included logistical (e.g., distance, cost), psychological burden, perceived lack of benefit, and discrimination/social stigma concerns. : Some psychosocial factors related to GT for rare diseases overlap with those in literature on GT for common conditions. Identified factors represent targets for theory-informed, person-centered interventions to support high-quality GT decisions that are informed and aligned with patient/family values and preferences.