Autosomal dominant is one of many ways that a trait or disorder can be passed down through families.
In an autosomal dominant disease, if you get the abnormal gene from only one parent, you can get the disease. Often, one of the parents may also have the disease.
Inheriting a disease, condition, or trait depends on the type of chromosome affected (nonsex or sex chromosome). It also depends on whether the trait is dominant or recessive.
A single abnormal gene on one of the first 22 nonsex (autosomal) chromosomes from either parent can cause an autosomal disorder.
Dominant inheritance means an abnormal gene from one parent can cause disease. This happens even when the matching gene from the other parent is normal. The abnormal gene dominates.
This disease can also occur as a new condition in a child when neither parent has the abnormal gene.
A parent with an autosomal dominant condition has a 50% chance of having a child with the condition. This is true for each pregnancy.
It means that each child's risk for the disease does not depend on whether their sibling has the disease.
Children who do not inherit the abnormal gene will not develop or pass on the disease.
If someone is diagnosed with an autosomal dominant disease, their parents should also be tested for the abnormal gene.
Nussbaum RL, McInnes RR, Willard HF. Patterns of single-gene inheritance. In: Nussbaum RL, McInnes RR, Willard HF. Thompson & Thompson Genetics in Medicine. 8th ed. Philadelphia, PA: Elsevier; 2016:chap 7.
Scott DA, Lee B. Patterns of genetic transmission. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 80.