Abstract
PURPOSE: In this study, the authors sought to characterize the language phenotype of fragile X syndrome (FXS), focusing on the extent of impairment in receptive syntax, within-syndrome variability in those impairments in relation to gender, and the syndrome specificity of those impairments. METHOD: The Test for Reception of Grammar, Version 2 ( Bishop, 2003), was used to examine the overall receptive syntactic skills of adolescents with FXS ( n = 35; 30 males, 5 females), adolescents with Down syndrome (DS; n = 28; 18 males, 10 females), and younger typically developing (TD) children ( n = 23; 14 males, 9 females) matched on nonverbal cognition. Performance on specific grammatical constructions and error types was examined for a subset of matched participants. RESULTS: Participants with FXS had overall receptive syntax scores that were lower than those of the TD participants but higher than those of the participants with DS; however, there was no difference in performance between the FXS and DS groups when females were excluded. Grammatical constructions that were especially difficult for participants with FXS and those with DS were identified, especially relative clause constructions and reversible constructions requiring attention to word order encoded by syntactic features. CONCLUSION: The current findings have implications for understanding the nature of the language learning difficulties of individuals with FXS and for language interventions.