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lilyo
I also chose 100% with that same reasoning!!!
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lilyo
@usmlecrasher, Yes it does so which is why if they inherited they have 100% chance of developing colon cancer later in life and the question was confusing because it didnt ask what is the percentage that this patient will have children with this mutation? It might be my language barrier but I don't know.
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diegolc26
Its a little tricky bk they want you to think the probability of developing cancer IF the offspring HAS the mutation, which is 50%. I mean, he has 50% chances of inheriting the cancer developing mutation. Thats how I think they want to trick us.
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mbourne
@cryus_em, you're putting way too much emphasis on the word "eventually". Either way the question and answer makes sense. It's an AD disease, so the chance of the offspring inheriting it would be 50% (and if they inherit it, they WILL develop adenocarcinoma of the colon, so the answer is still 50%).
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heenaasnani
If they inherit the mutation (chances of inheriting the mutation is 50%), they will develop the carcinoma for sure. I hope this helped.
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allora__
I understand that if she is heterozygous Aa the odds she passes the allele down is 50%, but can you please explain how we can assume she is heterozygous to begin with? If she were homozygous AA, then there would be 100% chance that her children inherit the disease. Feel like I may be missing a simple concept here..
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plaguedbyspleen
@allora_ I had to think long a hard about this too but then it came to me. For her to be autosomal dominant, both her mother and father would have to be heterozygous. Then both would have to give her the allele. The stem just mentions her father and grandfather so you can assume the mother did not have the disease.
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plaguedbyspleen
Correction: for her to be AA her parents would both have to be AT LEAST heterozygous Aa.
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I don't know why I feel the correct answer is 100%. The ques states, "what is the chance that offsprings will EVENTUALLY develop cancer?, not inherit the mutation"
Prophylactic colectomy or else 100% EVENTUALLY progress to CRC.