Advances in prenatal testing technologies have been able to answer more questions for expecting parents regarding the health of their baby. Now, using noninvasive prenatal testing, expecting parents can get prenatal screening without the risk of invasive procedures.
When exploring prenatal screening options, it is advised that expecting parents seek help from a genetic counselor. Your physician and counselor can explain each test and what the results mean in terms of further testing, and will help you sort through any emotions that may come up during the process.
One topic of discussion that will be addressed with a genetic counselor is family history and any potential risk that one of the parents is a carrier of a genetic condition. To understand if you are a carrier for a genetic disorder, it is important to understand how genes are inherited and how they are expressed in individuals.
How Genes Are Inherited
Each individual has two copies of every chromosome (a structure that carries genes), or 23 pairs of chromosomes. One copy of each chromosome is inherited from the mother, and the other copy is inherited from the father..
Dominant and Recessive Genes
Each gene has a dominant and recessive form. A dominant gene will express itself, or will be physically visible in the individual, even if coupled with a recessive gene. A recessive gene will only be expressed if it is coupled with another recessive gene. In other words, the recessive gene is "hidden" when paired with a dominant gene.
When a genetic abnormality is located on a recessive gene, it will only be expressed when an individual inherits another copy of this recessive gene with the same genetic abnormality .
Individuals as Carriers
Individuals who are healthy, but have an abnormality on a recessive gene, are characterized as carriers. This means that the gene does not physically present itself in the individual because there is a healthy dominant gene that takes precedence; however, there is a risk that this individual is a carrier of the recessive gene and the abnormality may be passed down to their child.
If the carrier wants to have a baby with an individual who is also a carrier of the same genetic mutation, their child faces the possibility of inheriting two recessive mutated genes, thereby inheriting the genetic condition.
Working with a Genetic Counselor
If you believe that you may be a carrier of a genetic disorder, or if you know that a genetic condition has been documented in your family history, speak to a genetic counselor to further understand the risk that your child may have of being born with this genetic condition or the risk that you have of passing this gene to your child.
