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Klinefelter syndrome, also called testicular dysgenesis, is the phenotype of the 47,XXY genotype and is characterized by male hypogonadism and infertility. Klinefelter Syndrome is probably the most common chromosomal variation found in humans. In random surveys, i ....

Middle of Essay
.... 47 chromosomes in each cell of their bodies instead of the usual number of 46. This extra sex (X) chromosome causes the distinctive make-up of these boys. All men have one X chromosome and one Y chromosome, but sometimes a variation will result in a male with an extra X. This is Klinefelter Syndrome and is often written as 47,XXY. There are other, less common variations such as 48,XXYY; 48,XXXY; 49,XXXXY; and XY/XXY mosaic. All of these are considered Klinefelter Syndrome variants. The major effect of the extra X chromosome in boys with Klinefelter Syndrome seems to be the function of the testes. The testes produce the major male sex hormone test ....