Private MD News

Microarray gets closer look at prenatal genetic abnormalities

Category: Female Specific Tests

A recent study published in the New England Journal of Medicine found that using a lab test method known as a microarray can detect fetal abnormalities on a smaller scale than the standard method karyotyping.

According to MedPage Today, during karyotyping, scientists look for chromosome disparities in live cells using a microscope to find anything that may indicate abnormal activity, whereas microarraying involves a high-resolution view of DNA that allows researchers to look for missing links or extra pieces in the DNA makeup.

While a microarray is the standard method for picking up on developmental delays in children, MedPage Today reported that there has been little research conducted on its effectiveness in pregnant women compared to karyotyping.

Ronald Wapner, M.D., of Columbia University Medical Center and his colleagues conducted a cohort study in which they analyzed 4,406 pregnant women with both methods, who were already undergoing genetic testing.

The results showed that while microarraying picked up on some genetic abnormalities, it missed larger chromosomal issues in the patients that karyotyping picked up on. The news source noted that microarraying was able to detect possible issues that could be harmful to patients in 3.4 percent of the findings. They also reported that this uncertainty could trigger anxiety in patients and cause them to terminate their pregnancies. To avoid this, the investigators stressed the importance of post-test counseling in which the pregnant mother would be able to speak to a genetic expert.

In an accompanying editorial, MedPage Today noted that Lorraine Dugoff, M.D., of the University of Pennsylvania, wrote that these new findings that microarraying yield make it hard to interpret whether they are harmful to a client that is why a database needs to be established, which may help create a criteria outlining which genetic variants are harmful and which are "pathologic."

Stillbirth detection
Another study, which was conducted by the National Institute of Child Health and Human Development, revealed that microarraying was more effective at diagnosing stillbirths that were attributed to genetic abnormalities. The March of Dimes defines a stillbirth as a fetal death that occurs within 20 weeks of the pregnancy.

The American Pregnancy Association reports that stillbirth occurs in nearly 1 in every 60 pregnancies. Some common causes include placental problems such as preeclampsia, which is a hypertensive condition. Approximately 15 to 20 percent of stillborn babies are a result of chromosomal disorders. Genetics can also play a role in birth defects such as structural malformations.