Most rare diseases are poorly understood, affected individuals struggle tobe timely diagnosed and to access tailored, appropriate, and affordablecare. Following pragmatist theory, individuals living with rare diseasesmay experience these obstacles as morally problematic situations, wherethey struggle with actualizing their cherished values amid their lifecircumstances. These embedded and contextualized lived episodes aredistinct from moral challenges and moral issues, which are more abstract,decontextualized, and speculative moral matters. We sought to uncoverthe moral matters of adults living with rare diseases in the qualitativeliterature while (...) elucidating the moral dimensions of morally problematicsituations. Moral matters were extracted from 25 qualitative studies andsubjected to thematic and interpretive analyses. The uncovered moralissues addressed abstract considerations relating to accessibility, limitedknowledge, and unpredictability of illness manifestations. Moralchallenges and morally problematic situations spanned across the fourphases of the medical trajectory: the diagnostic odyssey, the diagnosis,clinical care and treatment, and medical follow-up. Moral challengesnamely pertained to poor communication of diagnoses, lack of shareddecision-making, and lack of holistic support. Morally problematicsituations featured moral dimensions, namely (1) internal tensions (e.g.,being misunderstood), (2) constraints to agency (e.g., powerlessness anddisempowerment), in addition to (3) empowerment and selfadvocacystrategies (e.g., being assertive and demanding), notably in episodeswhere support from clinicians lacked. This study highlights the usefulnessof distinguishing these three types of moral matters in ethical analysis. Italso shows how moral dimensions of morally problematic situations carryexistential importance for affected individuals. (shrink)