Parents ask the nurse about the characteristics of autosomal dominant inheritance. Which statement is characteristic of autosomal dominant inheritance?

Question

a. Females are affected with greater frequency than males.
b. Unaffected children of affected individuals will have affected children.
c. Each child of a heterozygous affected parent has a 50% chance of being affected.
d. Any child of two unaffected heterozygous parents has a 25% chance of being affected.

Answer 1

ANS: C
In autosomal dominant inheritance, only one copy of the mutant gene is necessary to cause the disorder. When a parent is affected, there is a 50% chance that the chromosome with the gene for the disorder will be contributed to each pregnancy. Males and females are equally affected. The disorder does not "skip" a generation. If the child is not affected, then most likely he or she is not a carrier of the gene for the disorder. In autosomal recessive inheritance, any child of two unaffected heterozygous parents has a 25% chance of being affected.