Joan-Lluis Vives Corrons

By Joan-Lluis Vives-Corrons

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.

Part of the book: Rare Diseases

By Joan-Lluis Vives Corrons and Elena Krishnevskaya

The red blood cells (RBCs) carry oxygen from the lungs to the tissues, and for this, they must be able to deform. Accordingly, an impairment of RBC deformability is the cause of RBCs trapping and removal by the spleen and haemolysis. The most common causes for the decline in red cell deformability are the RBC membrane defects (abnormal shape or ionic transport imbalance), haemoglobinopathies (increased rigidity), or enzyme deficiencies (decreased anti-oxidant defences or ATP content). The most common cause of hereditary anaemia in childhood is hereditary spherocytosis (HS), characterised by a marked RBC deformabiity. A decreased RBC deformability has been found in hereditary haemolytic anaemias (HHAs) using the new-generation osmotic gradient ektacytometry (OGE), probably due to a combination of membrane protein defects and ionic imbalance. Therefore, OGE is currently considered the gold standard for the measurement of RBC deformability and the most useful complementary tool for the differential diagnosis of HHAs. Moreover, since several new forms of treatment are currently developed for hereditary RBC defects, the clinical interest of OGE is increasing. The aim of this chapter is to provide further information about the use of RBC deformability in clinical diagnosis and the OGE as a new challenge to decrease the frequency of undiagnosed rare anaemias.

Part of the book: The Erythrocyte