No, it is not possible. A family who share the same mutation in the Notch3 gene may be different from other families. In France, some families have similar mutations, but overall, the disease appeared in different families with specific mutations in each case.
Some mutations are more common in France and as a result, one may assume that some of these families are linked to a single genetic defect at the origin. The disease appears more in new families (chance of a birth, parents are not carriers, these are "de novo" cases).
Date: March 2012
CADASIL France General Meeting (www.CADASIL.com)