There is no doubt that knowing your family history can be important when it comes to you and your family’s health. Many conditions, such as heart disease and diabetes run in families due to a combination of both inherited genetic factors and shared lifestyle factors. Your medical provider will often ask you about your family history so they can suggest ways for you and your family to stay healthy, such as changes in diet or exercise.
But when it comes to the types of inherited health conditions included in carrier screening, a lack of family history doesn’t mean you are in the clear. Eighty percent (80%)1 of babies born with an inherited condition have no family history on either their mother’s or father’s side.
How can that be?
Many inherited conditions have what is called “recessive inheritance.” To be affected by one of these conditions, a child has to inherit a copy of a gene with a disease-causing change, or mutation, from each parent.
Having just one copy of a mutation doesn’t usually cause any symptoms, so many people are “carriers” for inherited conditions without ever knowing it. But if two people who are carriers for the same condition have children together, each child has a 1 in 4 (25%) chance of having the condition.
There are a handful of conditions that are looked at with carrier screening that can affect children even if only the mom is carrier. These are known as X-linked conditions because the mutations that cause these conditions are located on the X chromosome. As with conditions with recessive inheritance, women often don’t know they are carriers for these conditions.
Carrier screening gives you and your partner knowledge about your genetics that goes beyond what you can learn from assessing family history. This information allows you to find out if there are any risks to your current or future pregnancies so that you can plan and prepare. If you are a carrier for a condition (most people are), this information can be valuable to others in your family too.
1Blythe AS, Farrell PM. Advances in the diagnosis and management of cystic fibrosis.Clin Biochem.. 1984;17(5)277-283.