The Rare Anaemias

Anaemia is a common worldwide disorder mainly due to iron or vitamins deficiency. However, among the rare diseases (RD), there is a group associated with anaemia as main clinical manifestation or rare anaemias (RA). RA are mostly hereditary, and since they are little known, even for professionals, they remain undiagnosed, or misdiagnosed, for very long periods of time. This creates in patients, or, in their parents (if they are children) a permanent situation of stress due to the absence of a diagnosis, the impossibility to predict the course of the disease, and to the impossibility to perform, genetic counselling for future pregnancies. About 83 different RA have been described and their mechanism is in general a bone marrow or a red blood cell (RBC) defect. The most well-known RA are Fanconi anaemia, the thalassemia syndromes, sickle cell disease, hereditary haemolytic anaemias and paroxysmal nocturnal haemoglobinuria (PNH). The main objective of this chapter is to offer a review of the state of the art of RA knowledge and a way to facilitate their identification and final diagnosis through clinical manifestations and laboratory diagnostic tests.