roopashri
Forum Elite
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a man and women both having autosomal dominant disease , have 80% penetrance .They both are heterozygous.What is the probablity that they will have a normal baby ?
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| Geroo
Forum Guru
Topics: 114
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40
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| Doc2378
Forum Guru
Topics: 46
Posts: 688
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Can you please exlain that one Geroo...thanks in advance!
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Courage does not always ROAR. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow" - Mary Anne Radmacher
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| Geroo
Forum Guru
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well,the probability that the child will be affected is 75%.(50% heterozygous and 25% homozygous).as the disease has 80% penetrance that lowers the probability of the child being affected (75x80/100=60).so the probability that the child is affected it 60% so the probability of the child not affected is 40%.
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| Doc2378
Forum Guru
Topics: 46
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Thxs Geroo...no wonder I was getting it wrong...I was working with just 25% (AA) and not 75% (AA, Aa, Aa)......
Guess...I should call it a night now...can't seem to concentrate
___________________
Courage does not always ROAR. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow" - Mary Anne Radmacher
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| satyaking
Forum Junior
Topics: 5
Posts: 58
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We can also do it other way like this 20% of the autosomal dominant the gene is not penetrated,
then normal babies with the affected genotype is 20% of 75 = 15%, Then cross between AA & Aa
will have 25% probability with aa(normal genotype) child,So by adding 25+15 = 40%
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| roopashri
Forum Elite
Topics: 16
Posts: 190
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yes u all r right.
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