## **Core Concept**
Prader-Willi syndrome (PWS) is a genetic disorder caused by the loss of function of genes on chromosome 15 inherited from the father. It is characterized by a range of physical, mental, and behavioral features, including short stature, intellectual disability, and hyperphagia leading to obesity.

## **Why the Correct Answer is Right**
The correct answer can be deduced by understanding the typical features of Prader-Willi syndrome. Common characteristics include hypotonia, poor feeding in infancy, followed by hyperphagia and obesity, short stature, intellectual disability, and specific facial features.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Hypotonia and poor feeding in infancy are classic features of PWS, making this option incorrect as it is indeed seen in PWS.
- **Option B:** Short stature is another characteristic feature, making this option incorrect as well.
- **Option C:** Hyperphagia leading to obesity is a hallmark feature, which means this option is incorrect because it is seen in PWS.

## **Why Option D is Correct (Implicit)**
Since options A, B, and C describe common features of PWS, and without the specific details of each option provided, we infer that the feature not seen in PWS would be the correct answer. Typically, features not associated with PWS include tall stature, normal or high muscle tone in infancy, and conditions not related to the genetic loss on chromosome 15.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for PWS is the presence of **hyperphagia**, which often leads to severe obesity if food intake is not strictly controlled. Early diagnosis and management are crucial to prevent complications.

## **Correct Answer:** D.