Genetic testing for mutations in fibrillin-1 (FBN1) and other genes has become an important and reliable option to aid in the diagnosis of Marfan syndrome and related conditions. However, the results of genetic testing are not always straightforward. Therefore, working with a medical geneticist (a physician with training in genetics) or a genetic counselor is often necessary.
By understanding some basic information about genetic testing for Marfan syndrome, you can have a more meaningful discussion with your healthcare professionals and better comprehend the advantages and limitations of the testing process and the results.
Here are some of the common questions about genetic testing and Marfan syndrome.
- How is Marfan syndrome inherited?
- How is genetic testing done?
- In what situations might genetic testing be recommended?
- What is the cost of genetic testing?
Find these answers and more in the “Genetic Testing and Marfan Syndrome” download below:
How is Marfan syndrome inherited?
Each person has two copies of most genes in their cells. When a couple has a child, each
parent transmits only one copy to the child. If there is a mutation, or change, in one copy of a gene that produces a medical condition it is called a dominant condition. Marfan syndrome is a dominant condition in which one copy of the FBN1 gene has a mutation that affects the function of the protein, fibrillin-1, produced under the direction of the gene. If a potential parent has Marfan syndrome, each child born to that parent has a 50 percent chance of inheriting the mutated copy of the gene and, therefore, of having Marfan syndrome.
In what situations might genetic testing be recommended?
There are several instances when genetic testing may be beneficial:
- When adults with Marfan syndrome are considering having children.
- For a child with a parent who has Marfan, even before features are present in the child.
- In someone who has features of Marfan and several related conditions
- When someone has some features of Marfan, but do not have a definitive diagnosis.
- In families with a history of aortic aneurysm or dissection.
How is genetic testing done?
A gene is made up of DNA, which has four building blocks, called nucleotides (known by their abbreviated names: A, C, G, and T). The cell uses the nucleotides as instructions to make a specific protein. If there is a mutation or change in the nucleotide sequence, the protein may not function properly and cause a medical condition such as Marfan syndrome. Genetic testing looks for mutations or changes in the nucleotides. If a mutation or change is found in a gene, that person may have the medical condition associated with that gene mutation. If no mutation is found during the gene sequencing (genetic testing) and a person has clinical features of the disease, then a whole part of the gene could be missing. This is called a deletion. Further testing is required for confirmation.