What does genetic mean?


In many diseases genetic factors are important.  This means that part, or all of the risk, is passed down from one’s parents.  Certain diseases are caused by an abnormality in one single gene and CADASIL is one of these diseases. Genes produce proteins which are necessary for normal functioning of the body.  Everybody has two copies of each gene, one passed down from their mother, and one from their father. 


In CADASIL, an abnormality in only one of these two copies results in the disease.  We refer to this as autosomal dominant inheritance.  A consequence of this is that if you have CADASIL, you have one normal copy and one abnormal copy of the gene.  If you have a child, he or she will receive one copy of the gene from you, and one from your partner.  Therefore there is a 50/50 chance that any child of yours will have the CADASIL gene and will be at risk of developing CADASIL.  There is also a 50/50 chance that any child will inherit the normal copy of the gene and not be at risk of developing CADASIL.