Before we can answer this question, we need to talk about our genes. No, not your Levi’s, but rather, the building blocks of life. All of us have approximately 20,000 to 25,000 genes. Our genes contain all the necessary information we need in order to grow and develop properly. Genes are packaged inside larger, noodle-looking, structures that are called chromosomes. Typically, humans have a total of 46 chromosomes. We receive half, or 23, chromosomes from our mothers and the other half, or 23, chromosomes from our fathers, which is why we look a little bit like our moms and a little bit like our dads. Chromosomes are arranged by being lined up and paired up from largest to smallest, except for the last pair, which actually determine our sex. Females typically have two X, sex chromosomes, and males typically have one X and one Y sex chromosome.
That should bring us back to the original question….. so what does it mean to be a genetic carrier? Given that we have so many genes, some of them are bound to have changes (mutations) in them. Fortunately, since we have pairs of chromosomes, we, in general, have pairs of genes; one we inherited from our mom’s copy of the chromosome and one we inherited from our dad’s copy. So a ‘genetic carrier’ is someone who carries a mutation in one copy of a gene, but fortunately, the paired copy of that gene is functioning fine, compensating for the changed one. A person who carries a genetic mutation is generally considered unaffected, meaning they are healthy and would not be at risk for developing the particular condition they carry a mutation for, later on in life. Instead, especially during pregnancy, our concern becomes, could two parents, happen to carry gene mutations in the same gene? If yes, there is a 25%, or 1 in 4, risk that a baby would inherit a gene mutation from their mom, and at the same time, a gene mutation from their dad. If this were to happen then the baby would no longer have any functioning copies of the gene in question, to compensate, and would therefore be affected by a disorder.
There are hundreds of conditions that are inherited in this way, lots of which can now be tested for through several labs. However, when you start to evaluate so many potential targets, something is bound to come back positive…. So how do you know which, if any, carrier tests are right for you? A genetic counselor can help! We will ask questions about your family, including ethnic background, which helps us to determine which test(s) could be considered. Then together with your genetic counselor, you can decide if you want any of that information before or during your pregnancy. Finding out this information can be useful for testing either during pregnancy, via amniocentesis, or after birth.