Sex Chromosome Abnormalities

Claude J Migeon, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
Kara B Pappas, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA

Published online: April 2007

DOI: 10.1002/9780470015902.a0005943

In human subjects, the so-called sex chromosomes are the X- and the Y-chromosomes. The X-chromosome includes about 1500 genes, only a few of which are involved in sex development (such as DAX-1 and AR). The Y-chromosome includes a very limited number of genes, but one of them, SRY, is most important in male sex development. Multiple autosomal genes are also involved in sex development. Abnormalities of sex chromosomes can involve errors in the number of sex chromosomes, such as 45,X0 (Turner syndrome), 47,XXX, 47,XXY (Klinefelter syndrome), 47,XYY or mosaicism with at least one cell line having an aberrant number of sex chromosomes. Sex chromosome abnormalities also include aberrations of a single gene of the sex chromosome; resulting in errors in sex differentiation. This may result in 46,XX testicular disorder of sex development (DSD) 46,XY gonadal dysgenesis, 46,XX gonadal dysgenesis or ovatesticular DSD.

Keywords: Turner syndrome; Klinefelter syndrome; gonadal dysgenesis: complete or partial; true hermaphroditism; triple X syndrome; the 47,XYY syndrome

Figure 1. Sex differentiation pathway.
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Related Sub-Topics:

Chromosome Segregation | Developmental Disorders | Organogenesis | Growth and Development | Gene and Genome Structure and Organisation | Chromosomal Disorders | Genomic Disorders | Quantitative Genetics
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Article Title: Sex Chromosome Abnormalities
 
How to Cite close
Migeon, Claude J, and Pappas, Kara B(Apr 2007) Sex Chromosome Abnormalities. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005943]