How do most inherited heart diseases run in families?

Most gene mutations that cause inherited heart diseases, such as cardiomyopathies, arrhythmias, Marfan syndrome and other aortic diseases, are passed down in families in an autosomal dominant (AD) inheritance pattern. This means that the condition can affect men and women equally, and that it only takes one gene mutation to cause symptoms. An AD pattern also means that if you have a gene mutation, both of your parents, each of your siblings, and all of your children each have a 50/50 random chance to have this same mutation. Not everyone who inherits the mutation will develop symptoms at the same age, or to the same degree of severity (even within the same family). The picture below shows how people carry and pass on gene mutations when they follow an AD pattern.

Chart shows the dominant inheritance in people pedigree