1. What's the difference between various thalassemia?
Thalassemia includes several different types of anemia (red cell deficiency). There are two main types: α thalassemia and β thalassemia, which are classified according to which part of oxygen-carrying protein (hemoglobin) in red blood cells is lacking.
The most severe type of α thalassemia, mainly distributed in South Asia, China and the Philippines, will lead to fetal or neonatal death. However, most other children with α -thalassemia are mild, with only varying degrees of anemia.
However, the manifestations of β thalassemia vary from very severe to no effect on health.
Severe Mediterranean, known as Cooley anemia, was named after the doctor who first discovered it in 1925.
Intermediate thalassemia is a mild Cooley anemia.
Mild thalassemia may not cause any symptoms except abnormal hemoglobin.
2. How does thalassemia affect children?
Most thalassemia children seem to be healthy at birth, but they begin to become pale, tired, irritable and lose appetite within one or two years after birth. They grow slowly and often have skin jaundice.
If left untreated, the liver, spleen and heart of the child will gradually increase. The bones become thin and brittle, the facial bones are deformed, and the children with thalassemia look very similar. Heart failure and infection are the main causes of death in untreated thalassemia children.
3. What is the treatment for thalassemia?
Regular blood transfusion and antibiotics can improve the appearance of children with severe thalassemia. Although children with moderate thalassemia are required to have blood transfusion at the beginning of complications, blood transfusion is generally not required.
The purpose of regular blood transfusion for children with severe thalassemia (usually once every 3 ~ 4 weeks) is to maintain their hemoglobin close to normal level to prevent complications. This treatment is generally called "ultra-high-volume blood transfusion" to promote the growth and health of children, and also to prevent heart failure and bone deformation.
Unfortunately, repeated blood transfusion will lead to the accumulation of iron in the body, which will damage the heart, liver and other organs. A drug called iron chelating agent is recommended to remove excess iron from the body, so as to prevent or delay the problems caused by overload iron. This drug is usually injected subcutaneously by a portable pump when the child falls asleep every day.
Children with severe thalassemia treated by regular blood transfusion and iron-chelate mixture can survive for 20 ~ 30 years or even longer. Because the intensive iron chelation therapy was only introduced in the 1960s, long-term studies have shown that the treated individuals are still alive, even longer.
Thalassemia can also be treated by bone marrow transplantation. However, this treatment is only effective when a small number of patients' bone marrow matches the donor's bone marrow, and the bone marrow transplantation process is also full of risks and can lead to death.
4. How did this disease happen?
All types of thalassemia are transmitted only through heredity. It will not spread directly from children to normal children. The disease is passed on to offspring through parents who carry thalassemia-causing genes. The so-called "carrier" means that there is a normal gene and a thalassemia gene in individual somatic cells, and most carriers can live a completely normal and healthy life.
When both parents are carriers, their children have a14 chance to inherit thalassemia genes from their parents respectively, thus suffering from severe thalassemia; There is a 2/4 chance to inherit one normal gene and one abnormal gene, thus becoming the same carrier as parents; 1/4 chance to inherit two normal genes, and then completely get rid of the state of being sick or carrier. In the above situation, every time a woman is pregnant, the probability of having a thalassemia fetus is like this.
5. Is there any experiment to detect thalassemia?
Yes. Blood tests and family genetic tests can determine whether an individual is a thalassemia patient or carrier. In addition, prenatal examination can detect whether the fetus has thalassemia by villus biopsy and amniocentesis. Early diagnosis is very important, because early treatment can prevent complications as much as possible.
6. Can thalassemia be prevented?
At present, this disease cannot be prevented. However, through health education, trait testing, genetic counseling and prenatal diagnosis, families can be provided with enough medical information to help them have healthy children.
People who think they may be thalassemia patients or carriers should go to hospitals or genetic service centers to get the latest knowledge and carry out relevant tests, so as to detect whether they are carriers. Genetic consultants will help them make plans for their future families.
Prenatal diagnosis by gene analysis can diagnose the fetus with severe β and α thalassemia in early pregnancy and give medical treatment in time, which is an effective method to prevent this disease at present.
7. What relevant studies on thalassemia are currently under way?
Scientists are trying to find a better way to eliminate the overload iron in the body to prevent and delay the problems caused by the overload iron. They are studying and testing the effectiveness of various iron chelates in order to simplify the treatment process of this disease as much as possible. Scientists in the United States are committed to studying the effective forms of gene therapy, with a view to providing treatment for thalassemia patients one day. Gene therapy includes inserting the normal β globin gene (which is abnormal in disease) into the patient's stem cells, that is, the progenitor cells that later differentiated into various cells in the blood-undifferentiated mature bone marrow cells; Another way of gene therapy is to use drugs or other methods to mutate the pathogenic gene of fetal hemoglobin. People will produce fetal hemoglobin before birth, and after birth, natural genetic characteristics will "turn off" fetal hemoglobin and "turn on" adult hemoglobin. Scientists are looking for genetic switches to induce these changes, so that they can make the blood cells of thalassemia patients produce more fetal hemoglobin to compensate for the lack of adult hemoglobin.