Human Growth and Development / Unit 2 HGD 0165 short lesson, about 20 seconds
Chromosomal Disorders
Captions available
The idea
Chromosomal disorders involve a change in a chromosome's structure, such as a deletion, or in number, a missing chromosome or an extra one.
In practice
Down syndrome, trisomy twenty-one: three copies of chromosome twenty-one instead of two.
Where people slip
Down syndrome brings a range of intellectual disability and possible heart problems; the CDC counts about five thousand seven hundred US births a year.
Your place on the trail
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Builds on
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