If you or a family member are diagnosed with CADASIL, and genetic testing has confirmed your diagnosis, it is helpful to share your results with your family. Most people with CADASIL inherit the gene change from one of their parents. Siblings and children are at risk of having CADASIL and could consider genetic testing. Full siblings and children are your 1st degree relatives and share 50% of your DNA. Therefore, siblings and children of an individual with CADASIL have a 50/50 or 1 in 2 chance of having the disorder as well.
If it is not known by evaluating the family history, testing of a parent can help to determine which side of the family has the altered NOTCH3 gene that causes the disorder. This can allow extended family (aunts, uncles, and cousins) to know who is at risk. A detailed family history can also provide information about which family members are at risk for developing CADASIL. Predictive testing in asymptomatic at risk adults is available but it is highly recommended that the genetic testing process include genetic counseling for both pre- and post-test guidance. Clinical evaluation of at risk family members can also provide information about any symptoms or signs of CADASIL. Genetic testing of adolescents under the age of 18 for CADASIL, a serious disorder without a specific treatment, is not recommend by most medical professionals.
A genetic medical professional nearby can discuss information and testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
