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 are likely to be most affected. The project studied 61 elementary school aged boys and their families. Approximately 25% of the boys were found to also meet diagnostic criteria for autism. It was noted that when autistic behavior and FXS co-occur, the effect on development appears to be additive. The heart rates of the boys with FXS were significantly higher than of typically developing children, and their visual-motor skills were less than half than would be typically expected. Achievement test scores showed wide variability. The children with FXS were found to be hypersensitive to their environment and about 43% had clinically significant behavior problems in the classroom. By third grade, 85% of the children were in self-contained, rather than inclusive classrooms. Teachers reported that 55% of the children had at least one friend at school and parents reported that 72% had at least one friend in or out of school. In most cases, the friend was another child with a disability. In addition to these findings, strategies to teach reading skills are discussed in the report. Data were collected on families' needs and supports, but have not yet analyzed. Budget information, a list of presentations, and a list of published articles related to the study are included. (SG)