Fragile X Syndrome is caused by changes in which gene?

Fragile X Syndrome is indeed caused by changes in the FMR1 gene. This gene, located on the X chromosome, is responsible for producing a protein known as fragile X mental retardation protein (FMRP), which is crucial for normal neural development and functioning. Mutations or expansions in the FMR1 gene, particularly the repetition of the CGG sequence, lead to the silencing of the gene and a lack of FMRP production. As a result, individuals with Fragile X Syndrome experience intellectual disabilities, developmental delays, and various behavioral challenges.

The other genes listed do not relate to Fragile X Syndrome. For instance, the BRCA1 gene is associated with breast and ovarian cancer risk, and the TP53 gene is involved in tumor suppression. The term "ADHD gene" is not specific to any one genetic marker but refers broadly to a variety of genes associated with attention-deficit/hyperactivity disorder. Thus, the specificity and functionality of the FMR1 gene make it the correct answer in the context of Fragile X Syndrome.