The "cri-du-chat" syndrome is caused by change in chromosome structure involving

Options

A. deletion
B. duplication
C. inversion
D. translocation

Explanation

To solve the question regarding the "cri-du-chat" syndrome, we need to understand the nature of the chromosomal change that leads to this condition. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Cri-du-chat Syndrome
- Cri-du-chat syndrome is a genetic disorder characterized by a distinctive cry in infants that sounds like a cat. It is associated with developmental delays and various physical and intellectual disabilities.

**Hint:** Remember that cri-du-chat syndrome is linked to a specific chromosomal abnormality.

### Step 2: Analyze the Options
- The question provides four options regarding changes in chromosome structure: deletion, duplication, inversion, and translocation. We need to determine which of these changes is responsible for cri-du-chat syndrome.

**Hint:** Consider the definitions of each chromosomal change carefully.

### Step 3: Define Each Chromosomal Change
- **Deletion:** Loss of a part of a chromosome.
- **Duplication:** An extra copy of a part of a chromosome.
- **Inversion:** A segment of a chromosome is reversed end to end.
- **Translocation:** A segment of one chromosome is transferred to another chromosome.

**Hint:** Focus on how each type of change affects the genetic material.

### Step 4: Identify the Specific Change in Cri-du-chat Syndrome
- Cri-du-chat syndrome is specifically caused by the deletion of a portion of the short arm of chromosome 5. This means that a segment of this chromosome is missing, which leads to the symptoms associated with the syndrome.

**Hint:** Look for the specific chromosome involved in cri-du-chat syndrome.

### Step 5: Conclusion
- Based on the analysis, the correct answer to the question is **deletion**. This is the only option that accurately describes the chromosomal change responsible for cri-du-chat syndrome.

**Final Answer:** The "cri-du-chat" syndrome is caused by a change in chromosome structure involving **deletion**.