Low frequencies of apparently fragile X chromosomes in normal control cultures: A possible explanation

Edmund C. Jenkins, W. Ted Brown, Judith Brooks, Charlotte J. Duncan, Maureen M. Sanz, Wayne P Silverman, Kusum P. Lele, Annette Masia, Edward Katz, Robert A. Lubin, Sarah L. Nolin

Research output: Contribution to journalArticle

Abstract

Low frequencies of apparently fragile X [fra(X)] chromosomes have been reported in normal control, short-term, whole blood cultures, and they have been noted in both amniocyte and fetal blood cultures. However, there is currently no universal agreement on the lowest frequency for fra(X)(q27) that is diagnostic for the fragile X syndrome. Here, we present our observations on low levels of apparently fra(X) chromosomes in normal samples. We observed frequencies of 0.5% in short-term whole blood cultures and 0.9% in amniotic fluid cell cultures. In 1982, Steinbach et al. described nonspecific telomeric structural changes (TSC) and suggested that such low frequencies of apparently fra(X) chromosomes in normal material may be occurring by the same mechanism that is responsible for TSC formation. To determine if TSC formation can explain the significant baseline frequencies of fra(X) in normal controls, 10,457 cells were screened from 178 individuals referred for fra(X) analysis. Our findings indicated that TSC are not randomly distributed across chromosomes but tend to occur at specific sites. Based on our observations, we offer the hypothesis that the low frequency of apparent fra(X) in normal individuals may be due to nonrandom TSC distribution.

Original languageEnglish (US)
Pages (from-to)40-48
Number of pages9
JournalPathobiology
Volume54
Issue number1
DOIs
StatePublished - 1986
Externally publishedYes

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Keywords

  • Fragile X chromosomes
  • Normal controls
  • Telomeric structural changes

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Pathology and Forensic Medicine

Cite this

Jenkins, E. C., Ted Brown, W., Brooks, J., Duncan, C. J., Sanz, M. M., Silverman, W. P., Lele, K. P., Masia, A., Katz, E., Lubin, R. A., & Nolin, S. L. (1986). Low frequencies of apparently fragile X chromosomes in normal control cultures: A possible explanation. Pathobiology, 54(1), 40-48. https://doi.org/10.1159/000163342