This final report reviews the second phase of a life-span study of boys with fragile X syndrome (FSX), the most common known inherited cause of mental retardation. Males with the syndrome are more severely affected than females and in males, delays are usually evident in all the developmental domains, although cognitive and communication skills…

This paper reviews the research on fragile X syndrome, the second most common cause of mental retardation related to chromosomal anomaly. It notes that far more males than females are affected by the fragile X syndrome, which typically results in craniofacial changes, delays in growth and development, speech/language difficulties, and cognitive…