**Question:** Which of the following is an autosomal dominant genetic disorder?

A. Cystic Fibrosis
B. Huntington's Disease
C. Duchenne Muscular Dystrophy
D. Gaucher Disease

**Core Concept:** Autosomal dominant disorders are conditions that are inherited in a specific pattern, where an affected individual has a 50% chance of passing the mutation to each of their offspring. In the case of a genetic disorder, this applies to the gene responsible for the condition.

**Why the Correct Answer is Right:**

Duchenne Muscular Dystrophy (DMD) is an autosomal dominant genetic disorder caused by mutations in the dystrophin gene (located on the X-chromosome). Dystrophin is a protein that helps maintain the structural integrity of muscle cells, and its absence leads to progressive muscle degeneration and weakness.

**Why Each Wrong Option is Incorrect:**

1. Cystic Fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. This explains why it cannot be the correct answer, as it is inherited in a different pattern (i.e., both parents need to carry the mutated gene for their child to have the condition).
2. Huntington's Disease (HD) is also an autosomal dominant disorder but is caused by a CAG repeat expansion mutation in the HTT gene. This makes it different from DMD, as HD is a neurodegenerative disorder affecting brain neurons.
3. Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder caused by mutations in the DMD gene, explaining why DMD is not the correct answer for an autosomal dominant disorder.
4. Gaucher Disease (GD) is also an autosomal recessive disorder caused by mutations in the GBA gene. Similar to DMD, this explains why Gaucher Disease cannot be the correct answer for an autosomal dominant disorder.

**Clinical Pearl:** Inheritance patterns such as autosomal dominant, autosomal recessive, and X-linked recessive help guide the clinician in assessing the risk of transmitting a genetic disorder to offspring and provides valuable information for genetic counseling.

**Correct Answer:** Duchenne Muscular Dystrophy (DMD) is an autosomal recessive disorder caused by mutations in the DMD gene. Since it is inherited in a different pattern than autosomal dominant disorders, DMD is the correct answer to this question.