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The phenotype of the person in question 27 (A person has hemophilia. Which is the correct genotype?) includes having ________ because __________?

1) joint pain : the gene that codes for coagulation factors is defective, causing easy bleeding into the joints.
2) joint pain : the joint tissue is oxygen-starved due to deformed hemoglobin in the RBCs.
3) simian facial features : hemophilia is a teratogenic disorder caused by maternal alcohol abuse.
4) severely shortened arms and legs : a drug called thalidomide caused the mutated genotype.

1 Answer

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Final answer:

The correct genotype for a person with hemophilia is a mutation on the X chromosome, resulting in the inability to synthesize sufficient quantities of clotting factors. Hemophilia A is the most common form, accounting for 80% of cases, and is caused by a lack of factor VIII. Hemophilia B is the second most common form, accounting for 20% of cases, and is caused by a deficiency of factor IX. so, option 1 is the correct answer.

Step-by-step explanation:

The correct genotype for a person with hemophilia is a mutation on the X chromosome, resulting in the inability to synthesize sufficient quantities of clotting factors. Hemophilia is a genetic disorder that affects the body's ability to control blood clotting. Hemophilia A is the most common form, accounting for 80% of cases, and is caused by a lack of factor VIII. Hemophilia B is the second most common form, accounting for 20% of cases, and is caused by a deficiency of factor IX.

Because the mutated genes for hemophilia are located on the X chromosome, the disorder is typically passed from a healthy carrier mother to her male offspring. Males have one X and one Y chromosome (XY), so they only need to inherit one mutated X chromosome to manifest the disease. Females, on the other hand, have two X chromosomes (XX) and need to inherit a defective gene from both parents to have hemophilia.

People with hemophilia experience difficulties in blood clotting, resulting in bleeding from minor injuries, bleeding into joint spaces after exercise, and bleeding into urine and stool. Regular infusions of clotting factors from healthy donors can help prevent bleeding in hemophiliac patients.

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