Severe expressive-language delay related to duplication of the Williams-Beuren locus

N Engl J Med. 2005 Oct 20;353(16):1694-701. doi: 10.1056/NEJMoa051962.


The Williams-Beuren syndrome (WBS) locus, at 7q11.23, is prone to recurrent chromosomal rearrangements, including the microdeletion that causes WBS, a multisystem condition with characteristic cardiovascular, cognitive, and behavioral features. It is hypothesized that reciprocal duplications of the WBS interval should also occur, and here we present such a case description. The most striking phenotype was a severe delay in expressive speech, in contrast to the normal articulation and fluent expressive language observed in persons with WBS. Our results suggest that specific genes at 7q11.23 are exquisitely sensitive to dosage alterations that can influence human language and visuospatial capabilities.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Attention Deficit Disorder with Hyperactivity / complications
  • Child
  • Chromosome Deletion
  • Chromosomes, Human, Pair 7*
  • Female
  • Gene Dosage
  • Gene Duplication*
  • Humans
  • Language Development Disorders / complications
  • Language Development Disorders / genetics*
  • Male
  • Phenotype
  • Speech Disorders / genetics*