Klinefelters 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

Klinefelter's is a genetic "syndrome." A syndrome is a convenient label used for people who show a particular constellation of symptoms. In this case, the underlying genetic cause is seen by medical professionals as equivalent to having the syndrome. It is not possible to have this syndrome's label given to a patient without the underlying genetic abnormalities. However, it is possible to have one or more of the "symptoms" of the syndrome (more about those below) without having KS. Klinefelter's Syndrome is not a disease, you can't catch it, and other family members are usually normal.

Some topics in this essay:
Physical Symptoms, Symptomless Syndrome, People XXY, Klinefelter's Syndrome, Jim Kohl, Means Klinefelter's, XXYY You'll, sex chromosomes, 44 autosomes, autosomes +, klinefelter's syndrome, pattern 44 autosomes, xxy sex chromosomes, taller norm, medical professionals, pattern 44, androgen insensitivity syndromes, closer examination, underlying genetic, 44 autosomes +, models --,