What is the inheritance pattern of Huntington disease?

• A. Mitochondrial
• B. Autosomal recessive
• C. Autosomal dominant
• D. X-linked recessive

Answer: (C)

Autosomal dominant inheritance.

A single mutated HTT gene allele is enough to cause Huntington disease, and it affects males and females equally. Each child of an affected parent has a 50% chance of inheriting the condition. The disease is tied to a CAG repeat expansion, and larger repeats can lead to earlier onset, a phenomenon known as anticipation—especially when transmitted from father to child. This pattern distinguishes it from mitochondrial inheritance (maternal only), X-linked inheritance, and autosomal recessive inheritance (which requires two mutated alleles).