PATHOLOGY MCQ
GENETICS AND DISEASE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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All sons will have hemophilia
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all daughters will have hemophilia
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50% of daughters and 50% of sons have hemophilia
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100% of sons have hemophilia and 100% of daughters are carriers
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Detailed explanation-1: -A woman who is a carrier has: a 25% (one in four) chance of having a daughter who is a carrier. a 25% chance of having a son with hemophilia. and a 50% chance of having a child (boy or girl) who does not have the gene for hemophilia at all (Figure 2.5)
Detailed explanation-2: -Thus the correct answer is (D) 50% sons will have haemophilia. Note: Haemophilia is X recessive linked gene disorder. A carrier mother has 50% chance of transferring the disease to her daughter. An affected male will pass on the genes to the daughters.
Detailed explanation-3: -A female carrier can also pass the affected X chromosome on to her children. Sometimes females with bleeding symptoms are not tested for hemophilia because there is often a misbelief that women can’t have hemophilia but can only be carriers.