Table 1.

The essential elements and concepts of ‘disease’ and ‘rare’ incorporated in the core definition statement

Definition of Rare

− Recognizing all PLWRD − Using a population prevalence to characterize rarity − A global description while recognizing variability in geographical and country contexts − Recognizing other epidemiological thresholds may be better suited to some subgroups of rare conditions

Definition of Disease

− Based on a distinct clinical presentation or phenotype, aligning with the ICD − Inclusive of all rare conditions, irrespective of clinical severity − Inclusive of all rare conditions, irrespective of disease etiology − Inclusive of conditions that remain undetermined − Recognizing subgroups of rare diseases