Instant Access To 100,000+ Essays!

Underlying Causes of Klinefelter's Syndrome The usual pattern chromosomal pattern in a "normal" man is 44 autosomes [chomrosomes not associated with sex] + one X chromosome and one Y chromosome. In a "normal" woman the pattern is 44 autosomes + two X chromosomes. In the case of a man with Klinefelter's Syndrome, the defining genetic difference is that the person has at least two X chromosomes PLUS at least one Y chromosome. The chromosomal pattern is most often 44 autosomes + XXY. For simplicity, I'm going to write as if 44 +XXY is "the" Klinefelter's chromosomal description, but please keep in mind that there are variations, like 44 + XXYY. You'll notice that the sex chromosomes include both the XX that defines a female in most cases and the Y that causes male development. The X chromosomes are important, but for purposes of the embryo turning into a male, the Y is the important one. People with XXY are not hermaphrodites or intersexed - the Y chromosome(s) ensure that they will develop a penis instead of a clitoris, a scrotum instead of labia, and testes instead of ovaries (barring secondary abnormalities due to chomrosomal oddities or teratogenic exposures). In someone with KS, the cause of the XXY sex chromosomes was nond