What are the genes affected in hemophilia and sickle-cell anemia?

Answer 1

Females possess two X-chromosomes, whereas males have one X and one Y chromosome. Since the mutations causing the disease are recessive, a woman carrying the defect on one of her X-chromosomes may not be affected by it, as the equivalent allele on her other chromosome should express itself to produce the necessary clotting factors. However the Y-chromosome in men has no gene for factors VIII or IX. If the genes responsible for production of factor VIII or factor IX present on a male's X-chromosome is deficient there is no equivalent on the Y-chromosome, so the deficient gene is not masked by the dominant allele and he will develop the illness.

Answer 2

For sickle cell anemia, also known as sickle cell diease, its caused by a point mutation on the "hemoglobin beta gene (HBB)" found on the 11th chromosome. The hemoglobin carries oxygen around the body on red blood cells, so with the mutated hemoglobin, the blood cells shrink and form sickle shapes, which can block small blood vessels.

As for hemophilia, i just know its a bleeding and clotting disorder, which means that a scab won't heal itself or they bleed longer than they should. 90% of cases are from a mutation on the Factor VIII gene, 9% on Factor IX gene and the 1% on other clotting genes.
Also, males have a higher chance of having hemophilia than females because the Y-chromosome in men has no gene for factors VIII or IX, whereas both X chromosomes in women need to be affected in order to be hemophiliac.

Answer 3

in sickle-cell the heamoglobin is mutated and the cell becomes shaped like a sickle(u know an agric tool you can use toharvest grains like rice if you want to do it manually)so its the gene that supposedto control the formation heamoglobin that is affected but then there is usually a carrier who does not suffer from it but could pass it to and offspring also we have those suffering from it who usually have short life span but could pass it to and offspring and make the offspring a carrier or a patient depending on the partner
haemophia is more common in men than in women and it has to do with bloodclotting and is dangerous, could lead to excess bleeding and eventual death i think that's what i know about that but check wikipedia.have fun

Answer 4

More than 15,000 people in the United States have hemophilia (either hemophilia A or hemophilia B). A person with hemophilia has a missing or low supply of one of the factors needed for normal blood clotting. Depending on the level of these factors in the blood, hemophilia may be classified as mild, moderate, or severe. About 60% of persons with hemophilia are of the severe type. They are at risk for bleeding after dental work, surgery, and trauma. They also may suffer internal bleeding with no trauma or injury and without apparent cause. Repeated bleeds can lead to other health problems and disabilities, including chronic joint problems and loss of range of motion. About 15% of persons with hemophilia have moderate hemophilia. These people are at risk for bleeding after surgery or trauma, joint problems, and rarely, spontaneous bleeds. Twenty-five percent of people with hemophilia have mild hemophilia. Their disease may be so mild that it may go undetected until bleeding occurs after trauma or surgery.

The hemophilia gene is carried by females on one of their X-chromosomes and may be passed to their male offspring. This is why hemophilia is called an X-linked genetic condition. Female carriers of hemophilia have one X chromosome with a working (normal) gene and one X chromosome with a non-working (defective) gene. There is a 50% chance the carrier will pass the hemophilia gene on to male offspring. In other words, there is a 50% chance that each of her male children will have hemophilia. There is a 50% chance each of her daughters will also be a carrier.

In about a third of all cases, there is no family history of the disease, and hemophilia occurs as a result of a spontaneous gene mutation. In such situations, the presence of the hemophilia gene may only become apparent when the mother is tested for carrier status after giving birth to a son with hemophilia.

Any male who inherits the defective X-chromosome has hemophilia. This is because males, unlike females, have only one X-chromosome. The Y-chromosome is mainly involved in determining gender and does not contain genes for the production of clotting factors. Boys born to a father with hemophilia and a mother who is not a carrier will not have the disease. This is because boys get the X-chromosome from their mother and Y-chromosome from their father. However, all daughters born to men with hemophilia will inherit the father's hemophilia gene. This is because they get one X-chromosome from their mother and one X-chromosome from their father. Thus, they will be carriers.

Some female carriers have no health problems or symptoms related to carrying the hemophilia gene. These women are known as asymptotic carriers. However, other female carriers have low factor levels that are associated with bleeding problems. These symptomatic carriers may suffer excessive nosebleeds, bruising and bleeding after surgery, dental work, or childbirth. Stress, exercise, medication, and changing hormone levels (during menstruation, during and/or after pregnancy) all may affect the bleeding patterns of symptomatic carriers. Female carriers who have excessive bleeding should be evaluated by a doctor skilled in treating bleeding disorders. Local hemophilia agencies can offer information about medical and other community resources.


Sickle cell anemia is an inherited blood disorder characterized primarily by chronic anemia and periodic episodes of pain. The underlying problem involves hemoglobin, a component of red blood cells. Hemoglobin molecules in each red blood cell carry oxygen from the lungs to body organs and tissues and bring carbon dioxide back to the lungs.

In sickle cell anemia, the hemoglobin is defective. After hemoglobin molecules give up their oxygen, some may cluster together and form long, rod-like structures. These structures cause red blood cells to become stiff and assume a sickle shape.

Unlike normal red cells, which are usually smooth and donut-shaped, sickled red cells cannot squeeze through small blood vessels. Instead, they stack up and cause blockages that deprive organs and tissues of oxygen-carrying blood. This process produces periodic episodes of pain and ultimately can damage tissues and vital organs and lead to other serious medical problems. Normal red blood cells live about 120 days in the bloodstream, but sickled red cells die after about 10 to 20 days. Because they cannot be replaced fast enough, the blood is chronically short of red blood cells, a condition called anemia.

Sickle cell anemia is an autosomal recessive genetic disorder caused by a defect in the HBB gene, which codes for hemoglobin. The presence of two defective genes (SS) is needed for sickle cell anemia. If each parent carries one sickle hemoglobin gene (S) and one normal gene (A), each child has a 25% chance of inheriting two defective genes and having sickle cell anemia; a 25% chance of inheriting two normal genes and not having the disease; and a 50% chance of being an unaffected carrier like the parents.