Anaemia means that the haemoglobin concentration and the so called haematocrit in blood are lower than normal. In most, but not in all, of the many types of anaemia, there is also a decrease in the number of red blood cells.
According to the European Commission a disease is rare when its population frequency is less than 5 cases in 10,000 individuals. The rare causes of anaemia (rare anaemias) are an example of rare diseases (RD). Up to date, about 90 rare anaemias have been described.
Research into these diseases is difficult because there are so few patients.
Anaemia is congenital when it becomes apparent at birth or start later in life. Congenital anaemias are usually hereditary, too. At the beginning, newborns normally have blood haemoglobin concentration significantly higher than children and, for that reason, anaemia is generally recognized after the third month of life. But sometimes the patient doesn’t even know that he has one of those conditions because clinical manifestations (symptoms) are almost absent and the quality of life is not affected. However, in other cases, a severe lifelong chronic anaemia is apparent right after the birth and regular blood transfusions are necessary for maintaining the required minimum haemoglobin concentration for life.
Anaemia is hereditary when the condition is already predetermined in the genes of the individual concerned. Accordingly, in dominant pattern it can be passed on from parents to their children with the probability of 50 %. However, in recessive hereditary anaemias parents, and also brothers or sisters, can be healthy, because only the occurrence of two mutated genes causes the disease.
Genes are segments of the desoxyribonucleic acid (DNA) containing a complete set of instructions, usually coding for a particular protein. The genes are, for example, responsible for building all the proteins needed for our bodies to work correctly. They are arranged in precise arrays along the chromosomes.
Erythrocytes or red blood cells (RBC) are blood cells containing haemoglobin which are produced by the bone marrow and form an essential component of blood. RBCs are responsible for tissue oxygenation by assuring the oxygen transport to the different tissues of the body. Bone marrow is the spongy tissue filling the centre of your bones, i.e. the skull, sternum (breast bone), ribs, vertebral column (backbone), and pelvis which produces the erythrocytes, but also leukocytes and platelets.
Haemoglobin is a specialized protein present in the RBCs that is responsible for oxygen transportation from lungs to the tissues and gives the blood its characteristic red colour. Blood haemoglobin concentration is influenced by age and sex. Adult men have higher haemoglobin concentration than women and children.
The CBC is a common blood test that provides information about the three types of cells in your blood: red blood cells (erythrocytes), white blood cells (leukocytes) and platelets. The CBC always includes also the measurement of haemoglobin concentration, haematocrit (packed cell volume; PCV), mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH). Sometimes it includes also the reticulocyte count and the distribution of different forms of leucocytes.
The CBC is determined, very easily and fast, by automated haematology analyzers. They provide an accurate measurement of blood haemoglobin concentration which is crucial for the diagnosis of anaemia.
Although the haemoglobin concentration vary between healthy individuals anaemia is diagnosed and should always be further investigated when the concentration of haemoglobin is lower than the normal ranges showed below. The reference values have been obtained from Dacie and Lewis’ PRACTICAL HAEMATOLOGY, 10th Edition 2006, edited by S.M. Lewis, B.J. Bain and I. Bates:
Haematocrit also known as packed cell volume (PCV) is the percentage of red blood cells in relation to total blood volume. The reference values have been obtained from Dacie and Lewis’ PRACTICAL HAEMATOLOGY, 10th Edition 2006, edited by S.M. Lewis, B.J. Bain and I. Bates:
MCV is the average volume of each individual red blood cell. It can be approximately calculated by dividing the volume of PVC (haematocrit) by the number of RBCs. However, it is accurately measured by automated haematology analyzers used today in most laboratories. The result is reported in femtolitre (fL= 10-15 L). It is not influenced by sex but by age. The
MCH is the average amount of haemoglobin of an individual red blood cell. It can be approximately calculated by dividing the haemoglobin concentration by the number of RBCs. However, it is accurately measured by automated haematology analyzers used today in most laboratories. The result is reported in picograms (pg) per cell. It is not influenced by sex but by age. The reference values have been obtained from Dacie and Lewis’ PRACTICAL HAEMATOLOGY, 10th Edition 2006, edited by S.M. Lewis, B.J. Bain and I. Bates:
Reticulocytes are immature red blood cells. Their concentration in peripheral blood can be easily measured by automated instruments (reticulocyte count) and normally ranges from 1 to 2% of the RBCs but can vary considerably between different methods. Reticulocytes are often expressed as "absolute reticulocyte count" (% x erythrocyte count), which normally ranges from 30 to 100 per µl (= 10-9 L) blood.
A decrease of blood haemoglobin concentration reduces the oxygen supplied to the tissues. Oxygen is necessary for all the body cells to maintain energy production and for an optimal cellular metabolism. In case of anaemia, the deficient oxygen supply to tissues explains the classical clinical manifestations or symptoms: fatigue, loss of muscle strength, dizziness, shortness of breath, heart palpitations pounding in your head and ringing in your ears. Anaemia, when severe, can be also the reason for delayed growth in childhood, for impeding in sport activities or reduced progress at school. Congenital anaemia should be supposed only when iron deficiency, the most common cause of anaemia in children and young women, has been excluded.
Generally, hereditary anaemia is a chronic disease without a uniform treatment. This means that the patient will suffer from the disease, to a lesser or greater extent, during all life. Treatment, if any, depends on the particular mechanisms of the different congenital anaemias. This is a matter that deserves further investigation. Some patients, depending on the severity of anaemia, are symptomatically treated by blood transfusions.
Iron deficiency is the most common cause of anaemia. It occurs frequently in children during the period of growth or in women during menstruation and pregnancy. That is often believed to be the cause of anaemia, even when its origin is congenital or of any other acquired mechanism. In general, this is due to an insufficient history and clinical examination. Iron and vitamins are useful only when they are really necessary; that is when deficiency is proven by appropriate tests. Some congenital anaemias can lead to iron overload and, in such conditions, taking iron pills is extremely bad for health. Diagnosis of most of the congenital anaemias is not easy and specialist advice is generally required. Sometimes bone marrow examination by a haematologist is also necessary.
Most anaemias are common and easy to diagnose and treat. The best person to give you advice about anaemia is a physician. ENERCA advises you to visit, first of all, your general practitioner or family doctor. She/he will program all the necessary tests or find a specialist to discover the most probable cause of your condition. If that cause is rejected, a variety of less common causes is to be considered. In those cases specialist advice is generally required.
We are compiling a list of specialist centres for rare anaemias in Europe. You can also look at the “links” part of the website for further information about anaemia. ENERCA is at your service. Please don’t hesitate to contact us with any questions you may have about rare anaemias. Our email address is: firstname.lastname@example.org.