What is a common characteristic of Fragile X Syndrome?

Fragile X Syndrome is indeed primarily caused by a mutation in a single gene, specifically the FMR1 gene on the X chromosome. This mutation leads to the expansion of a CGG repeat sequence, which can disrupt the production of a protein essential for normal neural development and functioning. As a result, individuals with Fragile X Syndrome often experience varying degrees of intellectual disability, along with characteristics such as social anxiety, behavioral challenges, and sometimes physical features associated with the syndrome.

The focus on a single-gene cause is pivotal in understanding the genetic nature of Fragile X Syndrome, setting it apart from chromosomal conditions where multiple genes or entire chromosomes may be involved. While other options touch on aspects of Fragile X (such as its genetic basis and the fact that it can affect both boys and girls), the emphasis on the single-gene mutation effectively captures the primary causal mechanism behind the syndrome's manifestation. This understanding is crucial for educational psychologists in their assessments and interventions for affected individuals.