What inheritance pattern is associated with hemophilia A?

Hemophilia A is primarily associated with an X-linked recessive inheritance pattern. This means that the gene responsible for the condition is located on the X chromosome, and the disease typically manifests in males who have only one X chromosome. If a male inherits the mutated gene for hemophilia A from his mother, he will express the condition because he does not have a second X chromosome that could carry a normal gene to compensate for the defective one.

In females, who have two X chromosomes, the presence of one normal gene can typically result in a normal phenotype, even if they carry a mutated gene on the other X chromosome. As a result, hemophilia A is often less frequently expressed in females, who may be carriers of the condition without exhibiting severe symptoms. The relationship of hemophilia A to the female carriers and its manifestation in males is a classic example of X-linked inheritance. Understanding this pattern is crucial in genetic counseling and understanding the impact of the disorder within families.