What is the most common cause of inherited mental retardation?

Fragile X syndrome is recognized as the most common cause of inherited mental retardation. This genetic condition is caused by a mutation in the FMR1 gene located on the X chromosome, which leads to a variety of developmental issues, including intellectual disabilities. The prevalence of Fragile X syndrome surpasses that of other genetic disorders associated with intellectual disabilities, making it the most significant in terms of inheritance.

Down syndrome, while a notable genetic condition, is primarily due to the presence of an extra chromosome 21 and is not inherited in the same manner as Fragile X syndrome. The majority of cases arise from random chromosomal events rather than straightforward inheritance patterns.

Adequate prenatal care is crucial for ensuring the health and well-being of both mother and child, but it is not a genetic condition and therefore cannot be a cause of inherited mental retardation.

Phenylketonuria (PKU) is a metabolic disorder that can lead to intellectual disability if not managed through dietary restrictions. However, it is less common than Fragile X syndrome in the context of inherited mental retardation.

Overall, the significance of Fragile X syndrome as the most common inherited cause of mental retardation highlights its specific genetic basis and its impact on cognitive development.