Rare Disease - Characteristics

Characteristics

Rare diseases usually are genetic, hence chronic. EURORDIS estimates that at least 80% of them have identified genetic origins. Other rare diseases are the result of infections and allergies or due to degenerative and proliferative causes.

Classification of a disease's rarity also depends on the population being studied. Every form of cancer is rare among children, but some forms are common among adults.

Symptoms of some rare diseases may appear at birth or in childhood, whereas others only appear once adulthood is reached.

Research publications emphasize rare diseases that are chronic or incurable, although many short-term medical conditions are also rare diseases.