Canadian Health Information Management Association Exam 2025 – 400 Free Practice Questions to Pass the Exam

Duchenne's muscular dystrophy is an X-linked recessive disorder, which primarily affects males, while females can be carriers. Given that the child's mother is likely a carrier of the gene mutation responsible for the disorder, the inheritance pattern is critical in understanding the risk for siblings.

Daughters of a carrier mother have a 50% chance of inheriting one of the two X chromosomes that carry the normal gene and one that carries the mutation. This leads to a 50% chance that daughters will be carriers themselves, meaning they have inherited the gene mutation but typically do not express the disease due to their second normal X chromosome.

Sons, however, inherit only one X chromosome from their mother and a Y chromosome from their father. Since the disorder is X-linked, each son has a 50% chance of inheriting the affected X chromosome from their mother and subsequently developing Duchenne's muscular dystrophy.

Thus, the statement indicating that daughters have a 50% chance of being carriers and sons have a 50% chance of developing the disease accurately reflects this genetic understanding. This context highlights why the provided answer is correct and essential for understanding the inheritance pattern associated with Duchenne's muscular dystrophy.