Sleep-EEG in dizygotic twins discordant for Williams syndrome

Róbert Bódizs, Ferenc Gombos, Katalin Szocs, János M. Réthelyi, Patrícia Gerván, Ilona Kovács

Research output: Contribution to journalArticle

3 Citations (Scopus)


Background and purpose - Reports on twin pairs concordant and discordant for Williams syndrome were published before, but no study unravelled sleep physiology in these cases yet. We aim to fill this gap by analyzing sleep records of a twin pair discordant for Williams syndrome extending our focus on presleep wakefulness and sleep spindling. Methods - We performed multiplex ligation-dependent probe amplification of the 7q11.23 region of a 17 years old dizygotic opposite-sex twin pair discordant for Williams syndrome. Polysomnography of laboratory sleep at this age was analyzed and followed-up after 1.5 years by ambulatory polysomnography. Sleep stages scoring, EEG power spectra and sleep spindle analyses were carried out. Results - The twin brother showed reduced levels of amplification for all of the probes in the 7ql 1.23 region indicating a typical deletion spanning at least 1.038 Mb between FKBP6 and CLIP2. The results of the twin sister showed normal copy numbers in the investigated region. Lower sleep times and efficiencies, as well as higher slow wave sleep percents of the twin brother were evident during both recordings. Roughly equal NREM, Stage 2 and REM sleep percents were found. EEG analyses revealed state and derivation-independent decreases in a power, lack of an a spectral peak in presleep wakefulness, as well as higher NREM sleep a peak frequency in the twin brother. Faster sleep spindles with lower amplitude and shorter duration characterized the records of the twin brother. Spectra show a striking reliability and correspondence between the two situations (laboratory vs. home records). Conclusion - Alterations in sleep and specific neural oscillations including the a/a waves are inherent aspects of Williams syndrome.

Original languageEnglish
Pages (from-to)59-68
Number of pages10
JournalIdeggyogyaszati szemle
Issue number1-2
Publication statusPublished - Jan 30 2014


  • 7ql 1.23 microdeletion
  • A waves
  • Dizygotic twins
  • Sleep EEG
  • Sleep spindles
  • Williams syndrome

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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  • Cite this

    Bódizs, R., Gombos, F., Szocs, K., Réthelyi, J. M., Gerván, P., & Kovács, I. (2014). Sleep-EEG in dizygotic twins discordant for Williams syndrome. Ideggyogyaszati szemle, 67(1-2), 59-68.