Invited editorial comment: Cognitive variability in the fragile X syndrome

A. E. Chudley, R. De Von Flindt, Randi J Hagerman

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The fra(X) gene is highly associated with moderate to severe mental retardation (MR) in the majority of affected males, but mildly retarded and normally intelligent fra(X) positive males, usually with learning disabilities, have occasionally been reported [Hagerman et al, 1985]. No doubt, previous studies in fra(X) families may have overlooked some mildly affected males, but it is unlikely this alone explains the 20% deficit of affected males in these families [Sherman et al, 1985]. We would agree that all individuals at risk in fra(X) families undergo appropriate physical, psychological, and cytogenetic investigations. Does a specific pattern of disability exist for the fra(X) positive male? Several recent reports suggest that most affected males demonstrate higher verbal than performance scores on standard psychometric testing [Hagerman et al, 1985; Veenema et al, 1986], despite major speech abnormalities and language disabilities [Newall et al, 1983; Hanson et al, 1986]. Affected males usually show the lowest subtest scores in digit span (auditory sequential memory) and arithmetic and in general seem to be better visual learners then auditory learners [Hagerman et al, 1985]. These features frequently lead to attentional problems and hyperactivity in school for affected males. Very few intellectually normal fra(X) positive adult males have been reported, but in one such individual subtest score deficits were identified [Veenema et al, 1987]. This normal fra(X) positive adult male and a full scale IQ of 98 and an apparently normal cognitive profile. Theobald et al [1987] reported an 8-year-old boy with language and speech delay who performed normally in the block design, digit span, and vocabulary areas but poorly in similarities and memory. Complete subtest scores and a full scale IQ were not obtained. Thus, although most affected fra(X) positive males perform poorly in select areas of cognitive ability measurements, exceptions exist.

Original languageEnglish (US)
Pages (from-to)13-15
Number of pages3
JournalAmerican Journal of Medical Genetics
Issue number1
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • Genetics(clinical)
  • Neuroscience(all)
  • Neuropsychology and Physiological Psychology


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