Autosomal Recessive Disease
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 disease, both chromosomes in a pair must have a changed gene for the person to have the disease. 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 disease.
- 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 disease.
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 disease.
If neither parent carries the gene change, the child will not have this type of disease.
See a diagram of the chances of passing on an autosomal recessive disease.
|Kathleen Romito, MD - Family Medicine|
|Siobhan M. Dolan, MD, MPH - Reproductive Genetics|
|Last Revised||November 29, 2012|
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