Medical advances have transformed the rare disease cystinosis from fatal in childhood to chronic and manageable well into adulthood, creating new challenges for patients, families, and providers. In response, families are adapting strategies to meet the demands of the illness and its treatments during a developmentally dense stage of life. Method: The study uses a classic grounded theory approach to understand the experience of adults and emerging adults living with cystinosis. Data were collected through focus groups and/or semi-structured interviews with 46 individuals (22 patients and 24 parents) recruited through national cystinosis advocacy/support organizations. Constant comparative analysis guided data collection and analysis. Results: In the context of much uncertainty, these patients and families described interconnected strategies to negotiate childhood and adolescence, enter into adulthood with self-care skills, and integrate normative developmental tasks with adequate management of illness. Strategies included educating, regimenting, pushing/protecting, connecting, coming to terms, and finding a fit. Conclusions: As both the understanding of and treatment options for rare and genetic childhood diseases expand, health care providers and multidisciplinary teams should consider regularly assessing the strategies used by families to manage illness. Families and individuals adapt as treatment protocols evolve and as children survive into adulthood, facing new, and perhaps unexpected, developmental tasks. The strategies described by participants can help frame the expectations of families across rare disease groups and suggest new avenues for resources and support.