[Rare Diseases: chronic diseases that need a new approach].

The concept of Rare Diseases is relatively new. They are those processes "...that can be mortal or to cause a chronic weakening of the patient and who, due to its little prevalence, require combined efforts to treat them. For indicative purposes, a little prevalence is considered when is lesser than 5 cases per 10,000 people in the Community". The existence of these diseases is closely tied with orphan drugs, meaning all drugs, prosthesis, biological agents or dietetic preparations destined to the treatment of a Rare Disease. Besides, it is necessary to add two factors more: 1. The Primary Attention physicians do not feel very motivated in their knowledge and 2. These diseases need a complex sociosanitary attention, habitually more expensive than chronic diseases. By all exposed the Rare Diseases appear like a universe that requires a new sociosanitary approach from the health system.