Saturday, April 18, 2015
Inherited Disorders and Birth Defects
Is genetic testing available?
This question has been forwarded by Spine and Back Health:
Spina bifida is one of a group of birth defects of the neural tube - the structure that develops into the brain and spinal cord. It is often called open spine and affects the backbone and, sometimes, the spinal cord. Spina bifida happens in about one in every 2,000 live births.
Spina bifida happens very early in development during the first month of pregnancy. Researchers believe that genetic and environmental factors act together to cause spina bifida. Most babies with spina bifida are born to parents with no other family members affected. However, spina bifida can run in certain families. If one child has spina bifida, the risk of having another child with spina bifida is about one in 40. Spina bifida also can occur as part of a syndrome with other birth defects.
There is no genetic test to determine if a person has spina bifida or if he/she is at an increased risk to have a baby with spina bifida.
However, an ultrasound during the end of the first trimester/beginning of the second trimester can look at the brain, spinal column and spinal cord to see if spina bifida is present. The mother can also have her blood screened for certain substances called analytes - one of these analytes is called alpha feto protein. If it is increased in the mom's blood it may mean the pregnancy has an increased chance of the baby having spina bifida. This blood test - called maternal serum screening - is done in the second trimester for spina bifida. Finally, the mother can have an amniocentesis (using a needle to draw out some fluid that surrounds the baby) during the second trimester to see if there are increased levels of alpha feto protein in the fluid surrounding the baby.
Research shows that up to 70 percent of neural tube defects including spina bifida can be prevented if women take in enough folic acid. Because neural tube defects close so early in pregnancy, the March of Dimes recommends that "women take a multivitamin containing 400 micrograms of folic acid daily, and eat a healthy diet including foods rich in folic acid. This is the most reliable way of ensuring that a woman gets all the folic acid she needs."
Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University