Comparison of the 15q deletions in Prader-Willi and Angelman syndromes: Specific regions, extent of deletions, parental origin, and clinical consequences

R. E. Magenis, S. Toth-Fejel, L. J. Allen, M. Black, M. G. Brown, S. Budden, R. Cohen, J. M. Friedman, D. Kalousek, J. Zonana, D. Lacy, S. LaFranchi, M. Lahr, J. Macfarlane, C. P.S. Williams

Research output: Contribution to journalArticle

135 Scopus citations

Abstract

It has recently been shown that apparently similar deletions of chromosome 15q occur commonly in the Prader-Willi and Angelman syndromes. The distinctness of the syndromes suggests that the deletions are not identical. To address this possibility, the specific bands involved and the sizes of the deletions were compared in seven patients with Prader-Willi syndrome and 10 patients with Angelman syndrome using high-resolution G-, Q-, and fluorescent R-banding techniques. The parental origin of the nine cases of Angelman syndrome for which parents were available for study was determined. The same proximal and was deleted (q11.2) in both syndromes. In general, the deletion in patients with Angelman syndrome was larger, though variable, and included bands q12 and part of q13. All of the studied deletions in patients with Angelman syndrome were of maternal origin. This contrasts with the predominant paternal origin of the deletion in patients with Prader-Willi syndrome. Two possible reasons for these observations are postulated: 1) the deleted regions are different at the cytologic and/or molecular level because of different exchange points in meiosis in males and females or to different mechanisms of breakage in males and females, resulting in differing breakpoints; 2) the deleted regions are essentially the same, but differential expression of the genes in the homologous chromosome 15 has occurred (imprinting).

Original languageEnglish (US)
Pages (from-to)333-349
Number of pages17
JournalAmerican Journal of Medical Genetics
Volume35
Issue number3
DOIs
StatePublished - Jan 1 1990

Keywords

  • Differential expression of paternal and maternal genomes
  • Imprinting
  • Parental origin

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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    Magenis, R. E., Toth-Fejel, S., Allen, L. J., Black, M., Brown, M. G., Budden, S., Cohen, R., Friedman, J. M., Kalousek, D., Zonana, J., Lacy, D., LaFranchi, S., Lahr, M., Macfarlane, J., & Williams, C. P. S. (1990). Comparison of the 15q deletions in Prader-Willi and Angelman syndromes: Specific regions, extent of deletions, parental origin, and clinical consequences. American Journal of Medical Genetics, 35(3), 333-349. https://doi.org/10.1002/ajmg.1320350307