Down Syndrome is the most common chromosome abnormality in the United States. Every year, more than 6,000 babies are born with the condition.
With comprehensive genetic carrier testing, it is relatively easy to determine your risk of passing the condition to your offspring. And, thanks to modern medical advances it is possible for babies with Down Syndrome to live long, healthy lives.
What Is Down Syndrome?
Down syndrome, or Trisomy 21, occurs when a baby is born with an extra copy of their 21st chromosome. This abnormality results in physical and mental disabilities as well as a shortened life expectancy. Down Syndrome ranges in severity. Some people with the condition require life long care, while others are able to live independently with limited assistance.
How Is Down Syndrome Diagnosed?
The easiest way to determine your risk of having a baby with Down Syndrome is comprehensive carrier screening. Carrier screening uses a simple blood or saliva test to determine if you or your partner are carriers. A carrier is someone who has a gene abnormality. The majority of carriers are healthy and have no physical symptoms of a disease.
Down Syndrome is an autosomal recessive disorder. That means it takes two genes –– one from the mother and one from the father –– to inherit it. Carrier screening can help determine your risk.
What Are The Types Of Down Syndrome?
There are three types of Down syndrome, including:
Trisomy 21. Trisomy 21 causes an extra copy of chromosome 21 to occur in every cell. It is the most common type, affecting more than 350,000 people in the United States.
Mosaicism. Mosaicism means there’s an extra copy of chromosome 21 in some cells, but not all of them. Children with mosaicism experience less severe symptoms than those with Trisomy 21.
Translocation. Translocation occurs when an extra copy of chromosome 21 latches on to another chromosome. It is the least common type of Down Syndrome, affecting about 3% of people with the condition.
Who Is At Risk Of Having A Baby With Down Syndrome?
Any couple can have a baby with Down syndrome, but there are several factors that may increase your risk. For example, you are more likely to have a baby with Down syndrome if:
- You are 35 or older at the time of birth
- You have a family history of Down Syndrome
- You carry the genetic translocation
Fortunately, it is possible to determine the likelihood of Down Syndrome before you even conceive.
What If I Am A Carrier?
If you learn that you or your partner are carriers it does not necessarily mean you will pass the chromosome abnormality on to your child.
Once you receive the results of your carrier screening, your primary care physician or OB/GYN can refer you to a genetic counselor. A genetic counselor can better explain the results of your test and provide resources to help you plan for the future.