A 5-year-old male presents with mental retardation and is diagnosed with Fragile X syndrome. Which of the following is most likely to cause this syndrome?

Question

Quizplus · Accepted Answer

Fragile X syndrome is caused by a duplication of CGG repeats at fragile sites on the X chromosome. This leads to methylation and silencing of the FMR1 gene, which encodes for fragile X mental retardation protein (FMRP). This protein is important for neuronal development and synaptic plasticity, and its absence leads to the characteristic mental retardation and other features of Fragile X syndrome. Translocation, inversion, and nondisjunction are not directly associated with Fragile X syndrome.

A 5-Year-Old Male Presents with Mental Retardation and Is Diagnosed