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  #1  
Old 04-14-2010
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Default achondroplasia

A woman gives birth to a child apparent achondroplasia. Two other siblings are of normal stature for their age. A genetic consultation group is asked to review the case. Both parents are 42 years old, and there is no previous family history of this condition.

What is the most likely explanation for the occurrence of this defect in this family?

a. gonadal mosaicism
b. incomplete penetrance
c. new mutation in the maternal gamete
d. new mitation in the paternal gamete
e. nonpaternity
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  #2  
Old 04-14-2010
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Default hmm...

could it be A??
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Old 04-14-2010
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Default It's new mutation

This must be new mutation but I can't figure out whether C or D is the correct answer
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Old 04-14-2010
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D, my guess is cause Achondroplasia is correlated to old paternal age.
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  #5  
Old 04-15-2010
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Yeah. It is D. In achondroplasia, gene mutation increase with paternal age (fibroblast growth factor receptor gene)
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Old 04-15-2010
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Just an extra tidbit of info; both Achondroplasia AND MARFAN's Syndrome are correlated to advanced paternal age.
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  #7  
Old 04-15-2010
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yep guys d) dad is the problem here. this is a new mutation. risk increases with paternal age > 35 yo
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