What disorders are caused from too many or too few sexchromosomes?

1 Answer
Jun 9, 2017

There are several disorders caused by an abnormal number of sex chromosomes.


Normal male: XY
Normal female: XX

Turner's Syndrome (X)
This female has only one X chromosome. She has sexual development problems and is sterile. Her lifespan and mental functions are not affected.
This is common in zygotes but almost all are spontaneously aborted (miscarriage).

Super Female Syndrome (XXX)
This female is tall and slender and may have a small learning difficulty. Otherwise she appears normal and has no problems. Many females who have this do not know because the extra X chromosome forms a Barr body and is not used. Not spontaneously aborted.

Klinefelter's Syndrome (XXY)
This is a male because there is a Y chromosome. Has sexual development problems at puberty. Often a small effect on mental function. Almost all are infertile. No effect on lifespan. Not spontaneously aborted.

Jacob's Syndrome (XYY) (AKA Super male syndrome)
This male has normal fertility and sexual development. He is very tall, and may have severe acne and poor coordination as a teen. At most there may be a minor effect on mental function and social behavior. Not spontaneously aborted.