Autosomal recessive inheritance

Definition: An autosomal recessive condition requires two copies of an altered gene for the associated condition to manifest.
Carriers: Both parents are carriers for the same autosomal recessive condition, meaning they each have one normal gene and one altered gene.

During conception, each parent can pass on one of their two chromosomes—this is determined by chance.
This results in four potential combinations for their children:
- Combination 1: One normal gene from each parent (Child is unaffected and not a carrier).
- Combination 2: One normal gene from one parent and one altered gene from the other (Child is a carrier).
- Combination 3: One altered gene from one parent and one normal gene from the other (Child is a carrier).
- Combination 4: One altered gene from each parent (Child has the condition).

Each child has the following probabilities:
- Inheriting two normal genes: 1 in 4 (or 25%) chance - Child will not have the condition and not pass the altered gene.
- Being a carrier: 2 in 4 (or 50%) chance - Child inherits one altered gene and one normal gene.
- Having the condition: 1 in 4 (or 25%) chance - Child inherits the altered gene from both parents.

Each pregnancy has a:
- 1 in 4 (25%) chance for a child to inherit the autosomal recessive condition.
It is crucial to convey to parents that this probability remains the same for every pregnancy, regardless of previous child outcomes. Chance does not 'remember' past results.