Which syndrome is known as the most common form of intellectual disability?

The most common form of intellectual disability is associated with Down syndrome. While Fragile X syndrome is indeed a significant cause of intellectual disability and the most common known single-gene cause, Down syndrome occurs more frequently in the general population. It arises due to an extra copy of chromosome 21, leading to a range of developmental and cognitive delays.

Williams syndrome and Klinefelter syndrome are both associated with their own specific characteristics, but they are less prevalent as causes of intellectual disabilities compared to Down syndrome. Klinefelter syndrome, for example, is primarily related to male developmental and reproductive issues rather than being a predominant source of intellectual disability.

Understanding these distinctions highlights the importance of recognizing Down syndrome as the most common syndrome linked to intellectual disability, shaped by its higher occurrence in the general population and the broader implications it has for education and support.