Rare diseases have had a special status within European Union (EU) health policy since the late 1990s. According to key EU legal documents, rare disease patients are entitled to the same good quality care as others. These individuals are particularly vulnerable due to the "low prevalence" and "uniqueness" of their disease. To ensure that patients with rare disorders in Europe can access high-quality care in their respective countries, the Council of the European Union (2009) recommended that member states adopt plans or strategies for rare diseases. Poland adopted its first Plan for Rare Diseases in 2021. This article draws from bioethical and social science scholarship on vulnerability as well as ethnographic research that I conducted among people with rare metabolic diseases, their families, health professionals, and patient advocacy groups in Poland between 2016 and 2023. I examine instruments developed within healthcare policies that are tailored to rare diseases, notably the patient passport, which is a site of disjuncture (Appadurai, 1990) embedded in healthcare policies and practices tailored to people with rare diseases. I argue that although such instruments are meant to benefit patients, they almost exclusively focus on the patient's sick body and the needs of health professionals, who are unfamiliar with a given rare disease. Thus, these instruments may engender paternalistic practices and they may contribute to discrimination and stigmatization as well as to the datafication of health vulnerabilities. Furthermore, the focus on inherent vulnerability obscures its other "layers" (Luna, 2009, 2019) or "degrees" (Traianou and Hammersley, 2023)., (Copyright © 2024 Elsevier Ltd. All rights reserved.)