Select all of the following that are patterns typical of autosomal dominant inheritance.

Inhaltsverzeichnis Show

In this video, we will learn about Autosomal dominant inheritance where an affected individual has a mutation in one of their gene pairs.

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Chromosomes 1 to 22 are the autosomes, and the 23rd pair are the sex chromosomes. We have two copies of all autosomal genes. In an autosomal dominant condition, the mutation in one copy of the genes leads to disease. With each conception a parent passes on one gene from the pair. Which one they pass on is due to chance. In automosal dominant inheritance there is a 50% or 1-in-2 chance of an affected parent passing on the condition to their children. This is because there are four possible combinations of genes that the children of that couple can inherit. Two out of four of these combinations result in a child inheriting the abnormal gene and being affected with the condition.

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Two out of the four result in the child inheriting the normal copy of the gene and being unaffected. Features that may lead you to suspect an autosomal dominant inheritance pattern include both male and females being affected in roughly equal proportions, people in more than one generation being affected, and men and women both being able to pass on the condition to their sons and daughters. An example of an autosomal dominant condition is hereditary breast and ovarian cancer predisposition. This is known in the press a lot recently following Angelina Jolie’s decision to undergo prophylactic bilateral mastectomies and subsequent bilateral oophorectomies. Jolie, who has a pathogenic mutation in BRCA1, lost her mother, aunt, and grandmother to cancer.

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Here we can see that the pedigree has affected people in three generations.

In this video, we learnt about autosomal dominant inheritance, where an affected individual has a mutation in one gene of a pair.

The main features of autosomal dominant inheritance pattern include:

Males and females are affected in roughly equal proportions.
People in more than one generation are affected.
Men and women are both able to pass on the condition to their sons and daughters.

Angelina Jolie’s family tree in pedigree form Click to expand
© St George’s, University of London

The image above depicts a simplified version of Angelina Jolie’s family pedigree, illustrating how an autosomal dominant condition can be passed down through 3 generations.

The actress, who has a pathogenic mutation in BRCA1, lost a number of her immediate family to cancer: her mother, her aunt, and her grandmother.

Talking point

We can see that the emergence of a greater understanding of genomics has already led to some difficult choices. What are, if any, your views on this?

Image: ©“Angelina Jolie – World Economic Forum Annual Meeting Davos 2005” by Remy Steinegger / World Economic Forum. Licensed by CC BY-NC-SA 2.0

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updated: December 8, 2022

Definition

Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. “Autosomal” means that the gene in question is located on one of the numbered, or non-sex, chromosomes. “Dominant” means that a single copy of the mutated gene (from one parent) is enough to cause the disorder. A child of a person affected by an autosomal dominant condition has a 50% chance of being affected by that condition via inheritance of a dominant allele. By contrast, an autosomal recessive disorder requires two copies of the mutated gene (one from each parent) to cause the disorder. Huntington’s disease is an example of an autosomal dominant genetic disorder.

Narration

Autosomal dominant disorder. When geneticists talk about dominant disorders, they're usually referring to those rare disorders that are caused by a spelling change in the DNA of one copy of a gene. Now because the chance of passing on the altered gene copy to each child is 50%, you typically see the disorder in each generation of the family tree. For example, you might see it in the mother. You might see it then in the mother's parent or the mother's grandparents or even aunts and uncles. Although sometimes a person with a dominant disorder can be the first person in their family to have the spelling change, disorders such as Marfan syndrome and BRCA1 hereditary breast and ovarian cancer work in this way.

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What is typical of the autosomal dominant type of inheritance?

Autosomal dominant inheritance is a way a genetic trait or condition can be passed down from parent to child. One copy of a mutated (changed) gene from one parent can cause the genetic condition. A child who has a parent with the mutated gene has a 50% chance of inheriting that mutated gene.

What are the 4 types of patterns of inheritance?

Inheritance Patterns.

Autosomal Dominant Inheritance..

Autosomal Recessive Inheritance..

X-linked Inheritance..

Complex Inheritance..

What are the 5 patterns of inheritance?

There are five basic modes of inheritance for single-gene diseases: autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, and mitochondrial.