Molecular-clinical correlations in children and adults with fragile X syndrome

L. W. Staley, C. E. Hull, M. M M Mazzocco, S. N. Thibodeau, K. Snow, V. L. Wilson, A. Taylor, L. McGavran, D. Weiner, J. Riddle, R. O'Connor, Randi J Hagerman

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Introduction. - Fragile X syndrome is the most commonly known inherited form of mental retardation. The intellectual abilities range from a normal IQ with learning disabilities to severe mental retardation. In males, there is a tendency for IQ decline in childhood. The purpose of this study was to correlate variations of the molecular cytosine guanine guanine (CGG) amplification in the fragile X mental retardation-1 (FMR-1) gene with the clinical findings, including IQ and physical features. Methods. - Full-scale IQ and cytogenetic results in 116 individuals with the FMR-1 mutation were studied. The IQ testing was performed with age-appropriate standardized tests. Physical features were summarized in a physical index score for each patient. The FMR-1 results were determined with the OX1.9 probe and the following system was used: P1 indicates premutation; P2, large premutation to small full mutation; P3, full mutation; and P4, mosaic. Results/Conclusions. - The findings showed that those females with a small insert in the P1 range had a significantly higher IQ than other heterozygotes (P2, P3, and P4 categories). P4 males had a significantly higher IQ than P2 or P3 males. In cross-sectional age comparisons, the slope of the IQ decline was greater in P2 males than in P4 or P3 males.

Original languageEnglish (US)
Pages (from-to)723-726
Number of pages4
JournalAmerican Journal of Diseases of Children
Issue number7
StatePublished - 1993
Externally publishedYes

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


Dive into the research topics of 'Molecular-clinical correlations in children and adults with fragile X syndrome'. Together they form a unique fingerprint.

Cite this