How is Down syndrome diagnosed? How to diagnose Down syndrome

The harm caused by Down syndrome is very serious, so we must do a good job of prevention. If you want to confirm whether your baby has Down syndrome, you can do three tests: chorionic villus sampling, amniocentesis, and non-invasive DNA gene testing.

Down syndrome, also known as "congenital idiocy" or "trisomy 21 syndrome", specifically refers to the change of chromosome 21 from the normal 2 to 3. It is a disease caused by multiple gene aberrations of congenital chromosomal abnormalities and is one of the most common birth defects in my country. Most children with Down syndrome have severe intellectual disabilities and other problems, such as congenital heart disease, leukemia, gastrointestinal malformations, etc. They cannot take care of themselves and have a short life span. The average survival age is only 20-30 years old, and the IQ is generally between 20-50.

How to diagnose Down syndrome

1. Chorionic villus biopsy: Chorionic villus biopsy is usually performed in the early stages of pregnancy, approximately between the 6th and 9th weeks of pregnancy. Samples are taken in the uterus to obtain chorionic villus tissue with strong proliferation capacity, and the chorionic villus tissue is subjected to chromosome analysis and genetic diagnosis. Infant birth defects such as Down syndrome, familial Tay-Sachs disease, cystic fibrosis, etc. can be diagnosed through chorionic villus sampling.

2. Amniocentesis: Amniocentesis is a test in which 20 ml of amniotic fluid is extracted between 16 and 20 weeks of pregnancy to culture the cells shed by the fetus in the amniotic fluid and detect the chromosomes of the cells. This invasive test carries the risk of amniotic fluid leakage infection and miscarriage, but the probability of this risk is very low, only about 0.1%. In addition, if you miss the appropriate gestational age, you will no longer be able to do it.

3. Non-invasive DNA genetic testing: Non-invasive prenatal genetic testing is performed in the early or mid-pregnancy, approximately 12 to 24 weeks, by performing B-ultrasound and collecting 5 ml of peripheral blood from the pregnant woman, extracting free DNA, and analyzing whether the status of the fetal chromosomes is normal, with an accuracy rate of 99%. It is non-invasive, has a short cycle, no risk of miscarriage, and is highly accurate. It also provides a new option for pregnant women who do not accept or miss invasive testing.