Prenatal genetic testing gives parents-to-be more options

During pregnancy, there are a variety of tests performed to keep track of the health of both the mother and the unborn child. Prenatal genetic testing is optional but gives parents-to-be information about whether their baby is at risk for certain genetic disorders or birth defects.

Genetic disorders are caused by variations in a person’s genes or chromosomes. As Natalie Blagowidow, MD, medical director of the Harvey Institute for Human Genetics and director of the Prenatal Diagnostic Center at GBMC HealthCare explains, the screening process has evolved as science has evolved.

“We’ve been screening for sickle cell for more than 50 years. Over the years, other genetic disorders have been identified, like cystic fibrosis, and more recently spinal muscular atrophy (SMA). It’s really been in the last six to seven years that SMA has become more prevalently screened for.”

Spinal muscular atrophy refers to a group of hereditary diseases, the most common of which affects the SMN1 gene. Dr. Blagowidow explains, “SMN1 is called the survival motor neuron gene. When it doesn’t function normally, it leads to weakness in the muscles that help you with posture and strength, as well as eating and breathing. When untreated, severe forms of the disease are fatal in childhood.”

Dr. Blagowidow adds SMA is a recessive disorder, and most people don’t realize they have the gene for it.

“This means each parent must carry the gene, and if both parents do, there is a one-in-four chance that your baby will be born with SMA,” she says.

Testing for SMA (along with several other genetic diseases) is typically covered by insurance, when recommended by a doctor, Dr. Blagowidow says.

“There are more than 500 conditions a person could be screened for, but the basic panel looks at far fewer genes.”

If both parents are found to have abnormal SMN1 genes, there are options available to them.

“Typically, parents will meet with a genetic counselor who lays all the information out,” Dr. Blagowidow says. “They can do a diagnostic test to figure out if the pregnancy is affected. If the fetal test is positive, we can arrange for the couple to speak with experts in treating the disease. We then can help and support them, whether they opt to continue the pregnancy or not.”

Dr. Blagowidow mentions testing for SMA has been added to newborn screening in most states in recent years, but she says the earlier it can be identified, the greater the chances of treating it effectively.

“None of the SMA treatments are perfect, but once the child has symptoms, the treatment isn’t as beneficial,” she says. “This is why carrier screening is so important, because the parents can look to have treatment lined up once the baby is born.”

For parents who are on the fence about genetic testing, Dr. Blagowidow offers this perspective.

“You can benefit your child by knowing this. It can help you anticipate what’s going to happen.”

She adds that it’s not just unborn babies who may be affected by your choice to get screened.

“We’ve had patients who have preschool-aged children get carrier screening, and they’re found to have the same recessive gene. So, their child, who’s 4 years old and has undiagnosed symptoms, turns out to have the disease and now they know what they’re dealing with and can move forward with a more effective treatment plan.”

Dr. Blagowidow recommends talking to your doctor if you have any concerns about prenatal genetic testing.