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Genetic Disorders

Down Syndrome

Dis

Turner Syndrome

Dis

Down syndrome is a genetic disorder caused by an extra 21 chromosome.

Click here for an karyogram of an individual with down syndrome.

The reason for this occurs during meiosis. The chromosomes do not split correctly.  Instead of the cells getting one chromosome 21 each, one gets 2 21 chromosomes, while the other gets none.

This causes the infant to have 3 chromosomes 21.2 from one parent and one from the other. This is called Trisomy 21.

Click to enlarge the image

Tuner syndrome is a case of Monosomy on the X chromosome. Often the individual will have an entire X chromosome missing.

However, in some cases the sex chromosome is damaged or has abnormality.


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