Huntington disease can be grouped under one of the following categories. Name it.
a) Sex-linked dominant disorder
b) Sex-linked recessive disorder
c) Autosomal dominant disorder
d) Autosomal recessive disorder

Options

A. Sex-linked dominant disorder
B. Sex-linked recessive disorder
C. Autosomal dominant disorder
D. Autosomal recessive disorder

Explanation

To determine the category under which Huntington disease can be classified, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Huntington Disease**: Huntington disease is a genetic disorder that affects the brain, leading to physical and mental deterioration over time.

2. **Identify the Genetic Basis**: The disease is caused by a mutation on chromosome 4, specifically involving an abnormal repetition of the CAG (cytosine-adenine-guanine) sequence. In normal individuals, this sequence is repeated 10 to 35 times, but in those with Huntington disease, it can be repeated 42 to 100 times.

3. **Determine the Inheritance Pattern**: Huntington disease is inherited in an autosomal manner, meaning it is not linked to the sex chromosomes (X or Y).

4. **Classify the Disorder**: Since Huntington disease is caused by a mutation that is dominant, it means that only one copy of the mutated gene (inherited from either parent) is sufficient to cause the disease. This places it in the category of autosomal dominant disorders.

5. **Review the Options**:
- a) Sex-linked dominant disorder: Incorrect
- b) Sex-linked recessive disorder: Incorrect
- c) Autosomal dominant disorder: Correct
- d) Autosomal recessive disorder: Incorrect

6. **Conclusion**: Based on the above analysis, Huntington disease can be classified as an **autosomal dominant disorder**.

### Final Answer:
**c) Autosomal dominant disorder**