**Core Concept**
Cri du chat syndrome is a rare genetic disorder characterized by a high-pitched cry in infancy, growth delay, and intellectual disability. It is caused by a deletion of part of the short arm of chromosome 5.

**Why the Correct Answer is Right**
The deletion of the short arm of chromosome 5 leads to the loss of genes that regulate normal development, resulting in the characteristic features of Cri du chat syndrome. The cry is thought to be due to the abnormal development of the laryngeal muscles. The deletion can range from a small deletion to a large deletion of the entire short arm, with the size of the deletion determining the severity of the symptoms.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as Cri du chat syndrome is not caused by a deletion of chromosome 1.
**Option B:** This option is incorrect as Cri du chat syndrome is not caused by a duplication of chromosome 5.
**Option C:** This option is incorrect as Cri du chat syndrome is not caused by a translocation involving chromosome 5.

**Clinical Pearl / High-Yield Fact**
Cri du chat syndrome is also known as 5p deletion syndrome because the deletion occurs on the short arm (p) of chromosome 5. It is a rare disorder with an estimated incidence of 1 in 50,000 births.

**Correct Answer:** .