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Kaplan qbank is saying that Fragile X Syndrome is the most common cause of inherited mental retardation.

How come, isn't Down syndrome more common!

Anybody has an idea about this :notsure:
 

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Kaplan qbank is saying that Fragile X Syndrome is the most common cause of inherited mental retardation.

How come, isn't Down syndrome more common!

Anybody has an idea about this :notsure:
I'm guessing its because Fragile X is a triple repeat expansion on chromosome X, the FMR1 gene. This is inherited.

Downs syndrome is not inherited. It is a extra chromsome on tri 21 for whatever reason, but not inherited.

watch the language in the questions or answers, this will get people every time.
 

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Hello there... Just to confuse the issue further:

Kaplan's Path book says under the Down Syndrome section, that Down Syndrome is the "most common cause of genetic mental retardation."

Goljian calls Fragile X "Most common Mendelian disorder that causes mental retardation" and Down syndrome "Most common genetic cause of mental retardation"

So you're probably right - In the question the wording was the trick... Down syndrome is not inherited while Fragile X is.

Kaplan's path confuses the issue a little by not explicitly saying something like "due to genetic causes" or "not heritable" or something like that.
 
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