Language Trajectories of Girls with Fragile X Syndrome

Fragile X syndrome is the most common inherited cause of mental retardation. Females with fragile X syndrome (FXS), although less affected than males, range in cognitive functioning from average intelligence to severe mental retardation and often have social and behavioral problems, as well as specific learning disabilities. There are a few studies describing the language skills of adolescent and adult women with FXS, yet there are almost no studies concerning the language skills of girls with FXS. The proposed research will examine the language development of preschool and early elementary age girls with FXS and will focus on language characteristics common in older females with FXS (e.g., conversational difficulties). The study will also be the first to examine how variations in genotype may explain communication differences in girls with FXS. Participants will include 45 girls with FXS between 3 and 9 years of age at entry into the study. Data from this study will be compared to data that have already been collected on boys with FXS, as part of previous March of Dimes funding. Vocabulary, syntax, and conversational skills, as well as nonverbal cognitive level, will be measured in the girls’ homes or at their schools using standardized language assessments, such as receptive vocabulary tests, and nonstandardized measures, such as conversational language interactions. The analyses will examine specific aspects of language (i.e., analysis of noncontingent language) that the literature suggests may be affected by FXS. The size and methylation status of the trinucleotide repeat in the FMR1 gene of each girl with FXS will be determined. Phosphorimaging will be performed on Southern blots to determine the activation ratio (AR) for each girl. Measures of family factors will assess the responsiveness of the home environment. Statistical analysis will examine whether a child’s genetic status and other child and environmental factors relate to language development in girls with FXS and if there are gender differences in these language skills