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Definition

Autosomal dominant is one of many ways that a genetic trait or disorder can be passed down through families.

In an autosomal dominant disease, if you get the variant gene from only one parent, you can get the disease. Often, one of the parents may also have the disease. However, many autosomal dominant disorders' gene variant arises de novo, or for the first time in a family, in the affected person.

Information

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 variant gene on one of the first 22 nonsex (autosomal) chromosomes from either parent can cause an autosomal disorder.

Dominant inheritance means a variant gene from one parent can cause disease. This happens even when the matching gene from the other parent is normal. The variant gene dominates.

This disease can also occur as a new condition in a child when neither parent has the variant 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 variant 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 variant gene.

Examples of autosomal dominant disorders include Marfan syndrome and neurofibromatosis type 1.

References

Gregg AR, Kuller JA. Human genetics and patterns of inheritance. In: Lockwood CJ, Copel JA, Dugoff L, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 1.

Jones KL, Jones MC, Campo M. Genetics, genetic counseling, and prevention. In: Jones KL, Jones MC, Campo MD, eds. Smith's Recognizable Patterns of Human Malformation. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 2.

Korf BR, Limdi NA. Principles of genetics. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 31.

Scott DA, Lee B. Patterns of genetic transmission. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 97.

Sondheimer N. Patterns of single-gene inheritance. In: Cohn RD, Scherer SW, Hamosh A, eds. Thompson & Thompson Genetics and Genomics in Medicine. 9th ed. Philadelphia, PA: Elsevier; 2024:chap 7.

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