Neil,

We cannot know the exact recurrence risk until we understand the specific genetic cause in your family. I have listed the two possible ways the CDH could have been inherited in your family. In scenario 1 the chance of it to happen again with each pregnancy is 1 in 4 (25%). In scenario 2 the chance of it happening again is less certain because the mutation does not always cause a CDH when it is inherited. In these cases we would say the chance may be as high at 50% because with each pregnancy there is a 1 in 2 chance (50%) to pass on the mutation but the child may not develop the CDH. If we know the exact molecular cause of the CDH in the family, there are reproductive options that family can pursue to prevent the CDH from happening again if they wish.


1) A child inherits a genetic change from the mother AND the father. This genetic change alone in the mother or the father does not cause a CDH but when the child has BOTH genetic changes this causes a CDH. We think this type of inheritance is most likely when a family has more than one child affected.

2) A child inherits a genetic change from the mother OR the father and this causes the child to have a CDH. The parent with the genetic change may have a very mild CDH and never know that they have it or they may have other protective genes that cause them not to have a CDH even though they have a genetic risk. We think this type of inheritance is much less common than the first type. We think of this type of inheritance when a family has a child affected with a CDH and a parent is affected or a more distant relative like a aunt, uncle or cousin is affected.