A hemoglobinopathy represents a hereditary pathological change in hemoglobin. The main areas of distribution of hemoglobinopathies are the tropics and subtropics. The severity of the individual blood diseases depends on the respective genetic defect.
What is hemoglobinopathy?
According to abbreviationfinder, symptoms such as jaundice, fatigue and dizziness must be evaluated by a doctor promptly. If left untreated, hemoglobinopathy can lead to serious complications.
Hemoglobinopathies are genetic blood diseases that mainly occur in the tropics and in many Mediterranean countries. Around seven percent of the world’s population suffers from some form of hemoglobinopathy. These are usually autosomal recessive genetic mutations.
Heterozygous carriers of the respective mutation have a survival advantage over severe malaria infections. While the carriers of healthy genes often die of malaria and often do not reach the reproductive age, heterozygous carriers are better able to survive severe malaria crises. In this way, the mutated genes that can trigger homozygous hemoglobinopathies gain a selective advantage in the malaria regions.
Since malaria occurs particularly in the tropical and subtropical regions of the world, almost 30 percent of the population there have genes for various hemoglobinopathies. The different mutations also produce different forms of blood disorders. Specific properties of hemoglobin, such as oxygen affinity, stability, the ability to aggregate, the tendency to form methemoglobin, or even insignificant characteristics can be altered.
Hemoglobinopathies can basically be divided into two broad categories. There are thalassemias on the one hand and abnormal hemoglobins on the other. The main types of thalassemia are alpha and beta thalassemia. Gamma and delta thalassemias are less common. Hemoglobin is an iron-containing protein complex made up of four globins (from alpha to delta globin).
- The beta thalassemias that occur most frequently are divided into the milder beta thalassemia minor and the more severe beta thalassemia major.
- The alpha thalassemias include the clinically silent alpha thalassemia minima, the mild alpha thalassemia minor, the more severe alpha thalassemia major/HbH disease and Hb-Bart’s disease with the most severe form.
- The best known hemoglobinopathy with abnormal hemoglobin is the so-called sickle cell anemia.
Causes
Hemoglobinopathies are due to various gene mutations. Around 4,000 mutations are known in beta thalassemia that lead to changes in beta globin. The gene responsible is located on chromosome 11. To date, around 55 gene mutations have been uncovered in alpha thalassemia. The corresponding gene is located on chromosome 16.
The best-known abnormal hemoglobin is formed in what is known as sickle cell anemia. The cause of this disease is a point mutation on chromosome 11. It is the same gene that is responsible for coding beta-globin. Here, at position six of the beta-globin protein subunit, the amino acid valine is found instead of glutamic acid. This makes the beta globin chain unstable.
This instability causes red blood cells to crescent at low oxygen partial pressures. The hemoglobin retains the ability to bind oxygen. However, the breakdown of the beta-globin chain poses a risk of blood cell aggregation with the formation of blood clots.
The blood is very loosefastwith the release of free hemoglobin, arginase and oxygen radicals. As a result, nitrogen monoxide is consumed more. Since nitric oxide is responsible for widening blood vessels, its shortage causes them to narrow.
Symptoms, Ailments & Signs
The thalassemias offer a very variable clinical picture. Alpha thalassemia minima shows no symptoms at all. Those affected are merely heterozygous gene carriers. Even with thalassemia minor, there are hardly any symptoms. Only a slight anemia is observed. The intermediate form of thalassemia has moderate anemia and the major form has severe anemia.
Other symptoms are jaundice (jaundice) due to increased haemolysis, enlargement of the spleen (splenomegaly) or a heavy load on the heart. The affected children suffer from growth disorders, bone malformations and severe impairments of the internal organs. The anemia impresses with reduced performance, tiredness, headaches, increased heart rate and dizziness.
The immune system is generally weakened, resulting in frequent infections. In sickle cell anemia, the main symptoms are a lack of oxygen with breathing difficulties, frequent infections, dehydration, overacidification of the body (acidosis) and haemolysis. Infarcts of internal organs can occur as serious complications. The life expectancy of the patients is severely limited.
Diagnosis & course of disease
After the suspected diagnosis based on typical symptoms, hemoglobinopathies can be clearly diagnosed by chromatography or hemoglobin electrophoresis.
Complications
Hemoglobinopathy can lead to various complications and symptoms. In most cases, anemia occurs and the patient cannot engage in high loads or activities. Most of those affected also suffer from jaundice and growth disorders, which can lead to complications, especially in children.
The internal organs can also be affected by malformations. Tiredness sets in and the patient’s ability to perform is often limited. It is not uncommon for nausea and dizziness to occur, the patient feels ill and listless. Diseases and infections often occur due to the weakened immune system. As the disease progresses, the airways can become inflamed, which can be life-threatening for the patient.
Hemoglobinopathy is usually treated causally. There are no complications. In most cases, blood transfusions or stem cells are used to limit the symptoms of hemoglobinopathy. However, it is not always successful. Life expectancy can be limited if certain organ damage or malformations have already occurred.
When should you go to the doctor?
Symptoms such as jaundice, fatigue and dizziness must be evaluated by a doctor promptly. If left untreated, hemoglobinopathy can lead to serious complications. Therefore, medical advice should be sought at the first sign of illness. If severe headaches, poor posture or breathing difficulties occur, this must be clarified by the family doctor and treated if necessary. If the weakened immune system leads to infections, the affected person must consult a doctor immediately. Airway inflammation, persistent dizziness, and high fever are other warning signs that require treatment.
In the case of pneumonia, an examination in the nearest hospital is necessary in any case. Parents who notice symptoms such as growth disorders, organ function disorders or bone malformations in their child should inform the pediatrician. The doctor can make an initial diagnosis and, if necessary, refer the parents to a specialist clinic for hereditary diseases. Other contacts are specialists in internal medicine and therapists. Depending on the symptoms, a nutritionist and a lung specialist can also be called in.
Treatment & Therapy
Hemoglobinopathies are hereditary diseases and are therefore usually only treated symptomatically in milder cases. thetreatmentconsists, among other things, in the prevention of infections and dehydration (exsiccosis). Pain is treated with analgesics if necessary. Blood transfusions are necessary in an aplastic crisis.
More severe forms of hemoglobinopathies often lead to death at an early stage. Causal therapies that lead to healing are also necessary here. Stem cell transplants or allogeneic bone marrow transplants can be used for this purpose. For example, moderate to severe thalassemia requires a regular blood transfusion, which occurs every two to four weeks. This is to prevent severe anemia.
Unfortunately, the lifelong need for blood transfusions also leads to iron overload in the body. Iron binders must therefore also be administered parenterally by infusion or orally by tablets on a regular basis in order to flush the iron out of the body. For the causal treatment of sickle cell anemia, research is currently being carried out to correct the gene mutation. However, it is still too early for a practical solution.
Prevention
Since hemoglobinopathies are genetic, there is no recommendation for their prevention. If congenital blood diseases have already occurred in the family or relatives, their cause should be determined and, if you wish to have children, genetic counseling should be sought.
Aftercare
In most cases, those affected with hemoglobinopathy have very few or no special direct follow-up measures available. First and foremost, it is important to diagnose the disease quickly and, above all, at an early stage, so that there are no further complications or symptoms. The earlier the hemoglobinopathy is recognized and treated, the better the further course of this disease in most cases.
Most patients with this disease are dependent on taking various medications. It is always important to ensure that it is taken regularly and that the dosage is correct so that the symptoms can be properly alleviated. Likewise, if you have any questions or are unclear, you should first consult a doctor.
Bone marrow transplants are sometimes necessary for the patient to survive. Intensive and loving conversations with one’s own family or friends are often necessary, as this can prevent psychological problems or even depression. Contact with other people affected by hemoglobinopathy is often very useful, as this can lead to an exchange of information.
You can do that yourself
It is not possible to treat hemoglobinopathy by self-help. For this reason, those affected by this disease are always dependent on symptomatic treatment by a doctor, which is usually carried out with the help of blood transfusions.
If the hemoglobinopathy is supported with the help of medication, the person concerned should always ensure that the medication is taken regularly. Blood transfusions prevent anemia. Ideally, the patient should refrain from heavy and strenuous activities in order not to unnecessarily burden the body. Furthermore, the permanent blood transfusions can lead to a high iron content in the body. In order to prevent possible complaints and complications from this high content, those affected are dependent on taking iron binders. Likewise, foods that are rich in iron should be avoided in everyday life.
In many cases, contact with other people affected by hemoglobinopathy is helpful, as this can lead to an exchange of information that can make everyday life easier and improve the patient’s quality of life. In the case of psychological limitations, talking to people you trust is often very helpful.
