Heterozygous fragile X female: Historical, physical, cognitive, and cytogenetic features

A. Cronister, R. Schreiner, M. Wittenberger, K. Amiri, K. Harris, R. J. Hagerman

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174 Citations (Scopus)


Historical, physical, cognitive, and cytogenetic data were documented in 105 heterozygous fragile X [fra(X)] females and 90 controls in a prospective fashion. For comparisons, we divided heterozygotes and controls into those with cognitive impairment (IQ < 85) and normal IQ (IQ ≥ 85). The only finding that was significantly more frequent in impaired heterozygotes compared with impaired controls χ2 analysis was shyness. Features that were more frequent in normal IQ heterozygotes compared with normal controls were voluntary thumb dislocation and hyperextensible metacarpal-phalangeal (MP) joints. Comparisons among heterozygotes demonstrated more math problems, hand biting, strabismus, high-arched palate, hyperextensible finger joints, and flat feet in impaired heterozygotes than in normal heterozygotes. Premature menopause was present in 8 of 61 normal heterozygotes and in none of the impaired heterozygotes. A multiple regression analysis demonstrated a significant inverse correlation between the percent fragility and IQ for the heterozygotes as a group. However, no correlation existed between IQ and fragility when the percent fragility was 2% or greater. However, a higher percentage of fragility was positively correlated with the total number of physical findings present.

Original languageEnglish
Pages (from-to)269-274
Number of pages6
JournalAmerican Journal of Medical Genetics
Issue number2-3
Publication statusPublished - 1991
Externally publishedYes


  • Martin-Bell syndrome
  • cognitive impairment
  • fra(X) females

ASJC Scopus subject areas

  • Genetics(clinical)


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