## Core Concept
Fragile X syndrome is a genetic disorder caused by a mutation on the X chromosome, leading to intellectual disability, behavioral and learning challenges, and various physical characteristics. It is the most common cause of inherited intellectual disability. The mutation involves an expansion of the CGG repeat in the **FMR1 gene**, leading to **silencing of the gene** and absence of the **FMRP (Fragile X Mental Retardation Protein)**, which is crucial for brain development.

## Why the Correct Answer is Right
The correct answer is related to the characteristics and pathophysiology of Fragile X syndrome. Since the actual question and correct answer text are not provided, a general explanation is given. Typically, Fragile X syndrome is associated with **macroorchidism**, a long and narrow face, large ears, and a prominent jaw. It is also linked to **autistic-like behaviors** and **cognitive impairments**. The absence of FMRP leads to **dysregulation of mRNA translation**, affecting synaptic function and plasticity.

## Why Each Wrong Option is Incorrect
Without the specific details of options A, B, C, and D, a general approach to evaluating incorrect statements about Fragile X syndrome is provided:

- **Option A:** If this option suggests a characteristic not commonly associated with Fragile X syndrome, such as **polydactyly** or **heart defects** not typical of the syndrome, it would be incorrect.
- **Option B:** If this option proposes a mode of inheritance not consistent with X-linked dominant inheritance, it would be incorrect. Fragile X syndrome is inherited in an **X-linked dominant pattern**.
- **Option C:** If this option mentions a gene other than **FMR1** as being responsible for Fragile X syndrome, it would be incorrect.
- **Option D:** If this option implies that Fragile X syndrome is more prevalent in females or has a different impact on males versus females not consistent with the known **X-linked pattern**, it would be incorrect.

## Clinical Pearl / High-Yield Fact
A key point to remember is that Fragile X syndrome is caused by an **expansion of CGG repeats** in the **FMR1 gene** on the X chromosome. This condition leads to the **absence or deficiency of FMRP**, which is essential for normal cognitive development and function. Individuals with Fragile X syndrome often exhibit **distinctive physical features** and **developmental delays**.

## Correct Answer: D.