Fragile X boys: evolution of the mental age in childhood. Preliminary data on 10 prepubertal boys.

ABSTRACT

In this report we present data on the longitudinal evolution of the mental versus the chronological age in 10 fragile X boys diagnosed before the age of 6 years and compare these findings to the longitudinal evolution in children with Down syndrome (6 patients) and Williams syndrome (4 patients). The present findings suggest that the evolution of the velocity of development is more decreased in fra(x) boys compared to the two other groups.