Which of the following is true about Fragile X syndrome?
**Question:** Which of the following is true about Fragile X syndrome?
A. It is a genetic disorder caused by a mutation in the FMR1 gene on the X chromosome.
B. It primarily affects females due to the X-linked inheritance pattern.
C. It is characterized by intellectual disability and autism spectrum disorder.
D. Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) can improve symptoms.
**Core Concept:** Fragile X syndrome is a genetic disorder caused by a mutation in the FMR1 gene on the X chromosome. The FMR1 gene is responsible for producing the fragile X mental retardation protein (FMRP), which plays a crucial role in synaptic plasticity and neuronal development.
**Why the Correct Answer is Right:**
Fragile X syndrome is primarily caused by an expansion of CGG trinucleotide repeats within the FMR1 gene. When the number of repeats exceeds 200, the gene becomes unstable, leading to hypermethylation and silencing of the FMR1 gene. This results in the absence of FMRP, which disrupts normal synaptic plasticity and neuronal development, leading to the characteristic features of the disorder.
**Why Each Wrong Option is Incorrect:**
A. The statement about X-linked inheritance pattern is incorrect. While Fragile X syndrome affects males more severely due to their single X chromosome, both males and females can be carriers or affected individuals.
B. The statement about females is incorrect. Females (XY) are generally more variable in their presentation and severity, but the disorder affects both males and females.
D. Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) does not improve symptoms in Fragile X syndrome. NSAIDs are not effective in addressing the underlying genetic cause of the disorder and do not improve cognitive or behavioral symptoms.
**Clinical Pearl:** The FMR1 gene mutation can be detected through genetic testing, allowing for prenatal diagnosis and informed reproductive decisions. In females, the CGG repeat expansion may cause premature ovarian failure.
**Why Each Wrong Option is Incorrect:**
A. The statement about X-linked inheritance pattern is incorrect. While Fragile X syndrome affects males more severely due to their single X chromosome, both males and females can be carriers or affected individuals.
B. The statement about females is incorrect. Females (XY) are generally more variable in their presentation and severity, but the disorder affects both males and females.
D. Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) does not improve symptoms in Fragile X syndrome. NSAIDs are not effective in addressing the underlying genetic cause of the disorder and do not improve cognitive or behavioral symptoms.
**Clinical Pearl:** The FMR1 gene mutation can be detected through genetic testing, allowing for prenatal diagnosis and informed reproductive decisions. In females, the CGG repeat expansion may cause premature ovarian failure.