1. What's the difference between all kinds of 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) is lacking in red blood cells.
The most serious α thalassemia is mainly distributed in South Asia, China and the Philippines, which will lead to the death of fetus or newborn. However, most other children with α -thalassemia are mild, with only varying degrees of anemia.
However, the manifestations of β thalassemia range from very serious to no effect on health.
Severe thalassemia, called Cooley anemia, was named after the first doctor who discovered this disease in 1925.
Intermediate thalassemia is a mild Cooley anemia.
Mild thalassemia may not cause any symptoms except abnormal hemoglobin.
2. What effect does thalassemia have on children?
Most thalassemia children seem to be healthy at birth, but they begin to become pale, tired, irritable and have no appetite within one or two years after birth. They grow slowly and often have skin jaundice.
If left untreated, the child's liver, spleen and heart will gradually increase. The bones become thin and brittle, and the facial bones are deformed, which looks like a child with thalassemia. Heart failure and infection are the main causes of death in children with untreated thalassemia.
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 need blood transfusion at the beginning of complications, they generally don't need blood transfusion.
The purpose of regular blood transfusion (usually once every 3-4 weeks) for children with severe thalassemia is to maintain their hemoglobin close to normal level and 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 and damage organs such as heart and liver. It is recommended to use a drug called iron chelating agent to remove excess iron from the body, so as to prevent or delay the problems caused by iron overload. This medicine is usually injected subcutaneously with a portable pump every day when the child is asleep.
Children with severe thalassemia can survive for 20 ~ 30 years or even longer after regular blood transfusion and iron chelate treatment. Because intensive iron chelation therapy was only introduced in the 1960s, long-term studies have shown that the treated individuals are still alive or even longer.
Thalassemia can also be treated by bone marrow transplantation. However, this treatment is only effective when the bone marrow of a few patients matches the donor's bone marrow, and the bone marrow transplantation process is full of risks and may lead to death.
4. How did this disease happen?
All types of thalassemia are transmitted only through heredity. It will not be directly transmitted 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 a 1/4 probability of inheriting thalassemia genes from their parents respectively, thus suffering from severe thalassemia; There is a 2/4 chance to inherit a normal gene and an 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 giving birth to a thalassemia fetus is this.
5. Is there any experiment to detect thalassemia?
Yes Blood tests and family genetic tests can determine whether a person is a thalassemia patient or carrier. In addition, prenatal examination can detect whether the fetus has thalassemia through chorionic 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 learn the latest knowledge and carry out relevant tests to detect whether they are carriers. Genetic counselors will help them make plans for their future families.
Prenatal diagnosis through genetic analysis can diagnose that the fetus has severe β and α thalassemia in the early pregnancy and give timely drug treatment, which is an effective method to prevent the disease at present.
7. What relevant research on thalassemia is currently under way?
Scientists are trying to find a better way to eliminate the overload iron in the body, so as to prevent and delay the problems caused by 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. American scientists are committed to studying effective forms of gene therapy in order to provide treatment for thalassemia patients one day. Gene therapy includes inserting the normal β globin gene (abnormal in diseases) into the patient's stem cells, that is, the progenitor cells that later differentiated into various cells in the undifferentiated mature bone marrow cells of blood; 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 natural genetic characteristics will "turn off" fetal hemoglobin and "turn on" adult hemoglobin after birth. Scientists are looking for gene switches to induce these changes, so that the blood cells of thalassemia patients can produce more fetal hemoglobin to make up for the shortage of adult hemoglobin.