Autism Symptomatology in Boys with Fragile X Syndrome: A Cross Sectional Developmental Trajectories Comparison with Nonsyndromic Autism Spectrum Disorder

Angela John Thurman, Andrea McDuffie, Sara T. Kover, Randi J Hagerman, Leonard J Abbeduto

Research output: Contribution to journalArticle

24 Scopus citations


Although males with fragile X syndrome (FXS) are frequently described as demonstrating autism symptomatology, there is much debate regarding whether the behavioral symptoms representing the core domains of autism are the result of the same or different underlying neurological/psychological mechanisms. The present study used a cross-sectional developmental trajectories approach to compare the profiles of autism symptomatology relative to chronological age (CA), nonverbal IQ, and expressive vocabulary ability between individuals with FXS and individuals with nonsyndromic ASD. Results suggest that the onset of autism symptoms and their developmental trajectories in males with FXS differ in important ways as a function of CA, nonverbal cognitive ability, and expressive vocabulary relative to males with nonsyndromic ASD. Theoretical and clinical implications are discussed.

Original languageEnglish (US)
Pages (from-to)2816-2832
Number of pages17
JournalJournal of Autism and Developmental Disorders
Issue number9
StatePublished - Apr 23 2015



  • Autism spectrum disorder
  • Behavioral phenotype
  • Developmental trajectory
  • Expressive vocabulary
  • Fragile X syndrome
  • Nonverbal cognition

ASJC Scopus subject areas

  • Developmental and Educational Psychology

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