Warfarin acts by inhibiting the activity of the VKORC1 protein, which helps to produce functional clotting factors. There is a variant in the VKORC1 gene that lowers the dose of warfarin required for treatment, and individuals with this variant have increased risk of bleeding when they are treated with warfarin. This variant is found 1639 base pairs upstream of the translational start site. This variant likely:. a. decreases the activity of the VKORC1 protein. b. increases the activity of the VKORC1 protein. c. decreases expression of the VKORC1 gene. d. increases expression of the VKORC1 gene.

The correct answer - c. decreases expression of the VKORC1 gene.

Explanation:

Mutation of Guanine nucleotide into Adenosine is the reason for this particular type of mutation. This mutation expresses the less expression of the VKORC1 protein.

The mutation results in a decrease in the affinity of the binding site of the transcription factor which causes less expression. Since the VKORC1 protein is less in the body so Warfarin doses are decreased  

Thus, the correct answer is - decreases expression of the VKORC1 gene.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.