preggytips.com

The idea of physicians screening for inherited diseases in fetuses has long been an interesting subject. Soon, however, doctors may be able to do just that. Until recently, it was impossible to screen fetuses for disorders such as sickle cell anemia, thalassemia, and cystic fibrosis via a maternal blood test. Instead, mothers were subjected to amniocentesis, where a physician extracts a tiny amount of amniotic fluid from the sac containing the growing fetus. This procedure is risky and is known to cause miscarriage.

Researchers in Thailand and Hong Kong now say they have discovered a method in which to diagnose inherited “monogenic” diseases with a simple blood test. The monogenic diseases are sparked by a single inaccuracy in one gene of the DNA.
“Such diseases can be diagnosed by a simple blood test ... and by counting the relative ratio of the mutant genes against the normal genes,” Dennis Lo, researcher leader at Hong Kong’s Chinese University, said. The blood test, Lo said, is taken from the mother and bares no risk to the fetus.

According to Lo, the maternal blood test is possible because the DNA of the fetus circulates in the mother’s blood. Lo and some fellow researchers discovered this known fact many years ago.
Several researchers have since attempted to determine the best method to make a distinction between maternal DNA and fetal DNA, before it is possible to identify anomalies found in the DNA from the fetus. These efforts, however, have been unsuccessful for the most part.

In a recent article found in the Proceedings of the National Academy of Sciences, Lo and his researchers claimed they designed a counting structure that may possibly bring non-invasive prenatal analysis of monogenic disorders into the realm of reality.
Using exceedingly exact digital testing equipment, both normal and mutant DNA sequences are reviewed in maternal blood. The blood count is then utilized to determine the amount of distorted genes inherited by the unborn child and to decide the likelihood of the baby developing a monogenic disorder.

Lo, did note the accurateness of his technique depends on the amount of DNA from the fetus present in the maternal blood during testing.

If identified at its earliest stage, physicians have a better chance of treating the monogenic disease and gaining the best results. For example, thalassaemia is known to cause a reduction in fertility or, in some cases, infertility. However, when treated early, the quality of the patient’s life is greatly improved.