How is sickle cell anemia iherited?

Sickle cell anemia is inherited in an autosomal recessive pattern, which means that both copies of the gene must be mutated for the disorder to manifest.

- Individuals with two copies of the normal gene (HbA) are not affected by the disorder and are called homozygous dominant (HbA/HbA).

- Individuals with one copy of the normal gene and one copy of the mutated gene (HbS) are called heterozygous (HbA/HbS). These individuals are known as "carriers" because they do not have sickle cell anemia but can pass the mutated gene to their offspring.

- Individuals with two copies of the mutated gene (HbS/HbS) have sickle cell anemia and are called homozygous recessive.

This pattern of inheritance explains why sickle cell anemia is more common in certain populations where the frequency of the HbS gene is higher, such as in parts of Africa, the Middle East, and certain regions of the Mediterranean and the Americas.