What is thalassemia and how to prevent the birth of children with thalassemia?

The disorder of globin chain production in hemoglobin (Hb) caused by gene mutation is called thalassemia (also known as sea anemia). Alias: thalassemia, thalassemia. So what are the types of thalassemia?

1. What is thalassemia?

Thalassemia, also known as thalassemia, is a group of autosomal recessive genetic diseases. The clinical manifestations are chronic progressive hemolytic anemia with symptoms varying in severity. The middle and lower reaches of the Yangtze River and the southern provinces are high-incidence areas. Clinically, it can be divided into four types:

1. Severe cases: Anemia, hepatosplenomegaly, developmental delay, jaundice, and bone deformation occur within a few days after birth. Severe obstetric complications may also occur. Blood transfusion, iron removal therapy, and hematopoietic stem cell transplantation are required after birth. If not treated, the child often dies before the age of 5.

2. Intermediate type: mild to moderate anemia, hemoglobin is 60-90g/L. Children begin to experience anemia, fatigue, and mild jaundice at around 1 year old. Most patients survive to old age.

3. Mild type: that is, carriers of the thalassemia gene, with mild anemia or no symptoms. It is usually discovered during family history investigation and does not require treatment.

4. Silent type: There are almost no clinical manifestations, and it cannot be detected by general screening methods. Only genetic diagnosis can confirm the diagnosis.

The treatment for children with the disease mainly involves regular blood transfusions. Currently, the cost of blood transfusions and iron removal treatment for a child is 20,000 to 50,000 yuan a year. Based on an average life expectancy of 20 years, 200 patients will require an additional medical expense of 200 million yuan each year, which brings a huge economic and mental burden to the family and society.

If both husband and wife carry the same type of thalassemia gene, there is a 1/4 chance that the fetus will suffer from severe thalassemia. Currently, thalassemia screening, genetic diagnosis, prenatal diagnosis, and selective abortion to eliminate severely ill children are internationally recognized as the preferred measures for preventing thalassemia.

2. How to prevent the birth of children with severe thalassemia?

In order to prevent the birth of children with severe thalassemia, it is recommended that people who undergo pre-marital and pre-pregnancy checkups undergo routine thalassemia screening. For those who screen positive, the genetic type of both husband and wife should be diagnosed before pregnancy. There are four main steps:

Step 1: Blood routine test - initial screening

Mainly look at MCV (mean corpuscular volume) and MCH (mean hemoglobin). If both are low or one of them is reduced, it is considered a positive initial screening.

Step 2: Hemoglobin electrophoresis—preparation for genetic diagnostic analysis

Mainly look at HbA2 and abnormal hemoglobin. If HbA2 is elevated, referral for α- and β-thalassemia gene diagnosis is recommended; if HbA2 is decreased or normal, referral for α-thalassemia gene diagnosis is recommended after excluding iron deficiency anemia; if HbF is elevated, referral for β-thalassemia gene diagnosis is recommended.

Step 3: If either spouse is diagnosed with thalassemia, the spouse will undergo phenotypic screening and genetic diagnosis.

Step 4: If both husband and wife have the same type of thalassemia, prenatal diagnosis will be performed on the fetus.