HEREDITY
SEX LINKAGE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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No, at least one parent must have hemophilia in order to pass down the disorder
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No, both parents must have hemophilia in order to pass down the disorder
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Yes, the mother could be a carrier and pass down hemophilia to her daughters
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Yes, the mother could be carrier and pass down hemophilia to her sons
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Detailed explanation-1: -The son can get from the mother either her X chromosome with the hemophilia gene or her X chromosome with the normal blood clotting gene. If the son gets his mother’s X chromosome with the hemophilia gene he will have hemophilia. If he inherits his mother’s other X chromosome, he will have normal blood clotting.
Detailed explanation-2: -Males having one normal gene and females having two normal genes for Factor VIII are clear of the hemophilia A trait and will not transmit this defect to offspring. Males having one abnormal gene are affected with hemophilia and will transmit that abnormal gene to all their daughters, but to none of their sons.
Detailed explanation-3: -If the mother has one altered factor gene and the father does not have hemophilia, each son has a 50% chance of having hemophilia and each daughter has a 50% chance of having one altered factor gene, causing her to be a carrier or have hemophilia.
Detailed explanation-4: -If the mother is a hemophilia carrier, there is a chance that the baby will be born with hemophilia. In families with a known history of hemophilia, or in those with a prenatal genetic diagnosis of hemophilia, one can plan special testing for hemophilia before the baby’s delivery.
Detailed explanation-5: -Each daughter has a 1 in 2 (50%) chance of getting her mother’s hemophilia allele and being heterozygous. Overall, there is a 1 in 4 (25%) chance for each pregnancy that the baby will be a son with hemophilia and a 1 in 4 (25%) chance that the baby will be a heterozygous daughter.