## **Core Concept**
The question pertains to the genetic condition associated with a deletion on the paternal copy of chromosome 15. This condition is known as **Prader-Willi Syndrome (PWS)**. PWS is a genetic disorder caused by the loss of function of genes on chromosome 15 inherited from the father.

## **Why the Correct Answer is Right**
Prader-Willi Syndrome occurs due to the deletion or maternal uniparental disomy (where a person receives two copies of chromosome 15 from the mother and none from the father) of the paternal chromosome 15. The genes on this chromosome are normally expressed only from the paternal allele, a phenomenon known as **genomic imprinting**. The loss of function of these genes leads to the characteristic features of PWS, which include severe infantile hypotonia, poor feeding in infancy, followed by hyperphagia and obesity in childhood, short stature, and developmental delays.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not correspond to the condition associated with a paternal chromosome 15 deletion.
- **Option B:** This option might refer to another condition but is not the correct answer for a paternal 15 chromosome deletion.
- **Option C:** This option is incorrect because it does not accurately represent Prader-Willi Syndrome or the condition associated with the deletion of the paternal chromosome 15.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Prader-Willi Syndrome is characterized by **hypotonia in infancy** followed by **hyperphagia** leading to obesity if food intake is not strictly controlled. Early diagnosis and management are crucial to prevent complications.

## **Correct Answer:** . Prader-Willi Syndrome