Autosomal Recessive Conditions

Topic Overview

Autosomal recessive conditions are genetic diseases that are passed to a child through both parents' chromosomes .

Each person inherits 23 chromosomes from each parent and so has 23 pairs of chromosomes. Each chromosome contains genes . One or both of the chromosomes in a pair may contain a changed (mutated) gene that could cause a genetic disease. In an autosomal recessive condition, both chromosomes in a pair must have a changed gene for the person to have the condition. If only one chromosome has a changed gene, the person is a carrier and does not have symptoms.

If both parents carry the gene change, there is a:

  • 25% chance in each pregnancy that their child will inherit the changed gene from each parent (two genes) and have the condition.
  • 50% chance in each pregnancy that their child will receive one changed gene and be a carrier.
  • 25% chance in each pregnancy that their child will not receive the changed gene and be neither a carrier nor have the condition.

If only one parent carries the gene change, there is a 50% chance in each pregnancy that the child will:

  • Receive the changed gene and be a carrier.
  • Not receive the changed gene and be neither a carrier nor have the condition.

If neither parent carries the gene change, the child will not have this type of condition.

See a diagram of the chances of passing on an autosomal recessive condition .

Autosomal recessive conditions include Tay-Sachs disease , cystic fibrosis , sickle cell disease , autosomal recessive polycystic kidney disease (ARPKD), and phenylketonuria (PKU).

Credits

ByHealthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Martin J. Gabica, MD - Family Medicine
Adam Husney, MD - Family Medicine
Specialist Medical Reviewer Siobhan M. Dolan, MD, MPH - Reproductive Genetics

Current as ofFebruary 23, 2018