Autosomal dominant

Autosomal dominant means that you can inherit a trait or disease if one of your two gene copies has a defect. That single defect is enough to make it noticeable.

The word autosomal means that the gene is located on a regular chromosome (not on a sex chromosome). As a result, men and women have an equal chance of developing the condition.

In autosomal dominant inheritance, one parent usually has:

• one normal gene, and
• one gene with a defect.

With each pregnancy, a parent randomly passes on one of the two gene copies. Therefore, the following usually applies:

• 50% chance that a child will inherit the gene with the defect (and therefore may be predisposed to or have the condition)
• 50% chance that a child will inherit the normal gene (and therefore not have the predisposition)