Cognitive, language and social-cognitive skills of individuals with fragile X syndrome with and without autism

P. Lewis, Leonard J Abbeduto, M. Murphy, E. Richmond, N. Giles, L. Bruno, S. Schroeder

Research output: Contribution to journalArticle

118 Scopus citations

Abstract

Background: It is not known whether those with co-morbid fragile X syndrome (FXS) and autism represent a distinct subtype of FXS; whether the especially severe cognitive delays seen in studies of young children with co-morbid FXS and autism compared with those with only FXS continue into adolescence and young adulthood; and whether autism in those with FXS is 'true autism', i.e. reflects the same underlying problems as idiopathic autism. Method: We compared the non-verbal IQ of adolescents and young adults with co-morbid FXS and autism (n = 10) with those with only FXS (n = 44). We then created a subsample of those with FXS only, matched on non-verbal IQ, mental age and gender (n = 21) to the subsample of those with co-morbid FXS and autism. We compared the two groups on measures of expressive language, receptive language (lexical, grammatical morphology and syntactic patterns), and a theory of mind task. Results: Those with co-morbid FXS and autism had lower non-verbal IQs than those with only FXS. The participants with co-morbid FXS and autism did not perform as well as the cognitive ability- and gender-matched participants with only FXS on the three measures of receptive language or the theory of mind task; there were no differences on the expressive language measure. Conclusions: Our findings support the notion that those with co-morbid FXS and autism represent a distinct subtype of FXS, with more impairment in receptive language and theory of mind even when controlling for their lower non-verbal IQ relative to those with only FXS. The greater cognitive impairments observed in those with co-morbid FXS and autism continues into adolescence and young adulthood; and the autism seen in those with FXS appears to be the same as idiopathic autism.

Original languageEnglish (US)
Pages (from-to)532-545
Number of pages14
JournalJournal of Intellectual Disability Research
Volume50
Issue number7
DOIs
StatePublished - Jul 2006
Externally publishedYes

Keywords

  • Autism
  • Behavioural phenotypes
  • Cognitive behaviour
  • Communication
  • Fragile X
  • Intellectual disability

ASJC Scopus subject areas

  • Genetics
  • Health Professions(all)
  • Rehabilitation
  • Genetics(clinical)
  • Education
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health

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