What genetic diseases can be detected by prenatal testing?

Pregnancy must be a very important thing for women. Every woman hopes that her baby can be healthy. Therefore, before pregnancy, people usually do some pre-pregnancy examinations to check whether their bodies are healthy. The main purpose of pre-pregnancy check-up is to check whether you have a genetic disease. So what genetic diseases can be detected by pre-pregnancy check-up? Let's introduce it in detail below.

1. Thalassemia This is a group of hereditary hemolytic anemias. Their common feature is that due to defects in the globin gene, the synthesis of one or several globin peptide chains in hemoglobin is reduced or cannot be synthesized, resulting in changes in the composition of hemoglobin.

In southern provinces of my country, if a couple is a carrier of the same type of thalassemia, each time they are pregnant, there is a 1/4 chance that their children will be normal, a 1/2 chance that they will be carriers, and a 1/4 chance that they will be patients with major thalassemia. Therefore, this is a very important disease in terms of genetic counseling and prenatal diagnosis.

There are three clinical types of thalassemia:

(1) Severe: Anemia, progressive hepatosplenomegaly, jaundice, and developmental impairment occur within a few days after birth.

(2) Intermediate type: Mild to moderate anemia, most patients survive to adulthood.

(3) Mild type: Mild anemia or no symptoms, usually discovered when investigating family history.

Examination method: Blood examination may show: microcytic hypochromic anemia and small red blood cell size.

2. G6PD deficiency This is hereditary glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is the most common hereditary enzyme deficiency disease. Hereditary G6PD deficiency is an X-linked incomplete dominant inheritance. Mutation of the G6PD gene leads to reduced enzyme activity, and red blood cells cannot resist oxidative damage and are destroyed, causing hemolytic anemia.

Clinical manifestations: roughly the same as general hemolytic anemia, manifested as neonatal jaundice, favism (prone to develop the disease after eating broad beans), drug-induced hemolysis, infectious hemolysis, non-spheroid cell hemolytic anemia and other clinical types.

3. Hemophilia is a hereditary bleeding disease that causes a lack of coagulation factors, prolonging the plasma clotting time and leading to severe coagulation disorders. It can occur in both men and women, but the vast majority of patients are male.

Laboratory examination: ① Coagulation examination showed prolonged coagulation time (normal in mild cases) and poor prothrombin consumption (accounting for about 70% of patients). ② Abnormal coagulation factor measurement.