This report discusses the outcomes of a study that examined 216 comparably aged children and adolescents (ages 2-18) with fragile X or autism to determine whether longitudinal change in cognitive ability and adaptive behavior was similar in the two groups. Results found decreases in Intelligence Quotient scores in young children with fragile X as…

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…