What is the Difference Between Autosomal Dominant and Autosomal Recessive Disorders?

🆚 Go to Comparative Table 🆚

The main difference between autosomal dominant and autosomal recessive disorders lies in the inheritance pattern and the number of mutated genes required for an individual to be affected by the disorder.

Autosomal Dominant Disorders:

  • Inheritance pattern: A single copy of the mutated gene (from one parent) is enough to cause the disorder.
  • Examples: Huntington's disease, Marfan syndrome, and BRCA1 hereditary breast and ovarian cancer.
  • A child of a person affected by an autosomal dominant condition has a 50% chance of being affected by that condition.

Autosomal Recessive Disorders:

  • Inheritance pattern: An individual must inherit two copies of the mutated gene (one from each parent) to be affected by the disorder.
  • Examples: Cystic fibrosis, sickle cell anemia, Tay-Sachs disease, and phenylketonuria.
  • A child has a 25% chance of being affected by the disorder if both parents carry the recessive gene.

In summary, autosomal dominant disorders require only one mutated gene from a single parent, while autosomal recessive disorders require two mutated genes, one from each parent, for an individual to be affected. The inheritance patterns for autosomal dominant disorders result in a higher chance of passing on the disorder to offspring compared to autosomal recessive disorders.

Comparative Table: Autosomal Dominant vs Autosomal Recessive Disorders

Autosomal dominant and autosomal recessive disorders are two main subtypes of autosomal inheritance, which refers to the 22 numbered chromosomes as opposed to the sex chromosomes (X and Y). Here is a table comparing the differences between autosomal dominant and autosomal recessive disorders:

Feature Autosomal Dominant Disorders Autosomal Recessive Disorders
Inheritance Inheriting a single copy of a gene variant is enough to cause the condition. A child needs two copies of a gene variant — one from each parent — to develop the condition.
Risk to Children Half of the children of a parent with an autosomal dominant trait will get that trait. One quarter of children will get an autosomal recessive gene if both parents have it.
Symptoms in Parents The parent with an autosomal dominant trait will show symptoms of the condition. Both parents are carriers but do not have the autosomal recessive condition themselves, so they typically do not show signs and symptoms of the condition.
Examples Huntington's disease, achondroplasia, neurofibromatosis, familial adenomatous polyposis, Marfan syndrome. Cystic fibrosis, sickle cell disease, tuberous sclerosis, myotonic dystrophy, neurofibromatosis.

In autosomal dominant inheritance, a child needs only one copy of a gene variant to develop a condition, and typically, the affected parent will also show symptoms of the condition. In autosomal recessive inheritance, a child needs two copies of a gene variant—one from each parent—to develop a condition, and the parents are usually carriers without showing signs and symptoms of the condition.