Monday , March 8 2021

New blood test can diagnose genetic disorders from the first weeks of pregnancy



The research, published this week in the journal Nature Medicine, has created a test that analyzes 30 genes associated with dominant genetic diseases and can detect diseases such as sickle cell anemia, hemophilia or cystic fibrosis.

Knowing if a fetus has any genetic disorder at the time of its formation stage could be very useful to treat it properly. Therefore, researchers in Texas (USA) have created a test that allows diagnosing genetic disorders at the beginning of pregnancy by sequencing small amounts of fetal DNA into the mother's blood.

Noninvasive prenatal tests for chromosomal disorders have been in existence for some years now. In 2017, a test for recessive illnesses of a single gene was developed, which occurs when someone has two copies of a defective gene. This test is useful when it is known that one or both parents are carriers of hereditary illnesses.

The new test

Now, this new research, the results have been published in Nature Medicine, He has created a test that analyzes 30 genes associated with dominant genetic diseases (which occur when someone has only one copy of a defective gene). These usually occur due to a mutation in sperm, egg or embryo, and are more common when one of the parents is relatively large.

The test, which can detect diseases such as sickle cell anemia, hemophilia or cystic fibrosis, could be used after an ultrasound that has shown that the fetus has a skeletal anomaly.

If the test gives a positive result for a genetic disorder, then doctors may offer a more invasive test to confirm the diagnosis. If the result turns out to be positive, couples could receive genetic counseling so they can make informed decisions about how to manage pregnancy.

The results were successful, but more tests are needed

The research was led by Jinglan Zhang of Baylor College of Medicine, Texas, and analyzed blood samples of 422 pregnant women, from the nine weeks of gestation onwards, in clinics in the US. U., Europe and Asia. Some of them had abnormal results in ultrasonography that suggested skeletal disorders in the fetus: 32 gave positive mutations in one of the 30 genes in the test.

In addition, the researchers tracked in 147 cases, performing more invasive tests or postnatal tests. This way they could confirm that the initial tests with the mother's blood were correct

"The data so far shows that this test is promising and accurate to detect the mutations it is supposed to have," Zhang explains New Scientist. However, they will need the results of a much larger group of women to demonstrate that the test is clinically useful.

*This news has been published originally in N + 1, science that adds.


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