## Core Concept
The question pertains to the genetic disorder caused by a microdeletion on chromosome 15. This condition is associated with **Prader-Willi syndrome** or **Angelman syndrome**, depending on the parental origin of the deleted chromosome.

## Why the Correct Answer is Right
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are both caused by the loss of function of genes on chromosome 15 inherited from one parent. PWS results from the loss of function of genes on the paternal chromosome 15, while AS results from the loss of function of genes on the maternal chromosome 15. The correct answer, **Prader-Willi syndrome/Angelman syndrome**, is associated with a microdeletion on chromosome 15. This microdeletion leads to the characteristic features of these syndromes, which include developmental delays, intellectual disability, and distinct physical and behavioral characteristics.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is blank and does not provide a recognizable condition related to chromosome 15 microdeletion.
- **Option B:** This option is also blank and does not relate to any known condition associated with chromosome 15.
- **Option C:** Similarly, this option is blank and does not pertain to any condition caused by a microdeletion on chromosome 15.
- **Option D:** This option is blank as well and does not correspond to any genetic disorder related to chromosome 15.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the **parental origin of the chromosome 15** determines whether a patient develops Prader-Willi syndrome or Angelman syndrome. This is an example of **imprinting**, where the expression of a gene depends on its parental origin. Prader-Willi syndrome is characterized by severe infantile hypotonia, poor feeding, and failure to thrive, followed by hyperphagia and obesity if food intake is not restricted. Angelman syndrome is marked by developmental delays, speech impairment, and ataxia, along with a happy demeanor and frequent laughter.

## Correct Answer: D. Prader-Willi syndrome/Angelman syndrome