Rare diseases as a systemic stress test for inclusive education in Spain: institutionalisation and structural resilience from family narratives

Inclusive education is widely established as a normative principle across European education systems. However, its effective implementation remains uneven when schools encounter forms of diversity that fall outside stabilised diagnostic categories. Drawing on qualitative analysis of narratives from 224 families of students aged 3–18 with rare diseases in Spain, this study examines how low prevalence and high heterogeneity function as a systemic stress test for inclusive education. Using a Delphi-validated questionnaire and reflexive thematic analysis of 2,093 textual fragments, the study focuses on organisational conditions shaping school responses. Findings reveal recurring tensions, including contingent inclusion dependent on individual actors, diagnostic invisibility linked to limited organisational consolidation, divergence between curricular adaptation and relational belonging, and the role of family-mediated advocacy. Families also articulate an implicit model of an ‘ideal school’, characterised by stable, anticipatory, and structurally embedded support systems. The study proposes conceptualising rarity not only as an epidemiological condition but as a political-organisational category enabling evaluation of the structural embeddedness of inclusive principles. Advancing inclusion requires organisational infrastructures capable of sustaining complex diversity without repeated negotiation or family-driven activation of rights.