Why does a genetic condition sometimes appear to miss out a generation?
Some dominant genetic conditions can affect family members very differently. This is called variable expression. The condition does not actually miss out a generation, but some people have such mild symptoms of the condition that they appear to be unaffected. They may not even know that they have the condition. In conditions whih occur later in life (adult onset conditions e.g. inherited breast cancer and Huntington’s disease), people may have died earlier of unrelated causes leaving no time for the condition to appear, or the correct diagnosis may never have been given. However, the parents may have passed on the condition to their children.
