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Down Syndrome, Molecular Genetics of

Structural Determination Techniques (DNA, RNA and Protein)

  1. Charles J. Epstein

Published Online: 15 SEP 2006

DOI: 10.1002/3527600906.mcb.200300030

Reviews in Cell Biology and Molecular Medicine

Reviews in Cell Biology and Molecular Medicine

How to Cite

Epstein, C. J. 2006. Down Syndrome, Molecular Genetics of. Reviews in Cell Biology and Molecular Medicine. .

Author Information

  1. University of California, San Francisco, CA, USA

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Down syndrome (DS) is the commonest of the genetically caused forms of mental retardation. It occurs with a frequency of approximately 1 per 800 to 1 per 1000 live births, and its incidence increases with increasing maternal age. DS is caused by the presence of an extra chromosome 21 within the genome, which, in turn, results in a 50% increase in the expression of the genes contained on the chromosome. By mechanisms currently undefined, the increased expression of several genes on human chromosome 21 results in a syndrome characterized by mental and growth retardation, a distinctive set of major and minor congenital malformations, a variety of cellular abnormalities, and, later in life, by the development of Alzheimer disease.

Keywords:

  • Acrocentric;
  • Autosomes;
  • Centromere;
  • Meiosis;
  • Trisomy