Which statement correctly describes autosomal dominant inheritance?

Which statement correctly describes autosomal dominant inheritance?

• A. It requires both parents to be affected for transmission
• B. It has approximately a 50% chance of transmission from an affected parent to offspring
• C. It never affects males
• D. It is inherited exclusively through the mother

Answer: (B)

Autosomal dominant inheritance means a single mutated allele on an autosome is enough to cause the trait. Because of this, affected individuals usually have an affected parent, and the trait can show up in every generation. When an affected parent who carries one mutant allele (usually heterozygous) mates with an unaffected partner, each child has about a 50% chance of inheriting the mutation and being affected, while the other 50% will be unaffected. This pattern affects males and females equally and can be transmitted by either parent, not exclusively by the mother. The statement that transmission is roughly 50% from an affected parent best reflects this inheritance pattern. The other descriptions—needing both parents affected, never affecting males, or maternal-only transmission—do not fit autosomal dominant inheritance.

Autosomal dominant inheritance means a single mutated allele on an autosome is enough to cause the trait. Because of this, affected individuals usually have an affected parent, and the trait can show up in every generation. When an affected parent who carries one mutant allele (usually heterozygous) mates with an unaffected partner, each child has about a 50% chance of inheriting the mutation and being affected, while the other 50% will be unaffected. This pattern affects males and females equally and can be transmitted by either parent, not exclusively by the mother. The statement that transmission is roughly 50% from an affected parent best reflects this inheritance pattern. The other descriptions—needing both parents affected, never affecting males, or maternal-only transmission—do not fit autosomal dominant inheritance.