Anemia in the pediatric patient

hemophilia chromosome mutation :: Article Creator

Hemophilia Genetics - News-Medical.net

Hemophilia is a rare inherited bleeding disorder where the blood fails to clot normally due to a lack of blood clotting proteins known as clotting factors. The condition leads to spontaneous bleeding as well as excessive bleeding after surgery or injuries.

Image Credit: Nerthuz / Shutterstock.Com

Introduction

While small cuts are not so much of a concern for most people with hemophilia, internal bleeding that can damage organs and tissues in the body can be dangerous and life-threatening. Bleeding in the joints can cause chronic disease that is intensely painful, whereas bleeding in the brain can cause seizures and long-term paralysis. If bleeding cannot be controlled or affects a vital organ, it can lead to death.

People with hemophilia have an abnormally low level of either factor VIII or factor IX in their blood; therefore, the severity of their condition depends on how lacking these factors are.

Genetics

The two main types of hemophilia are caused by gene mutations that affect the levels of clotting factors in the blood. Mutation of the FVIII gene leads to hemophilia A, also called classic hemophilia, whereas mutations in the FIX gene lead to hemophilia B, which is also known as Christmas disease.

Hemophilia is an X-linked condition, meaning it mainly affects males. In the United States, about one in every 5,000 males are affected each year. Worldwide, around 400,000 individuals have the condition, which affects all ethnicities and economic groups equally.

Humans have 22 pairs of autosomal chromosomes and one pair of sex chromosomes, making a total of 46 chromosomes in each cell. In males, there is both an X chromosome and a Y chromosome, whereas females have two X chromosomes. Male offspring inherit their X chromosome from their mother and their Y chromosome from their father, while female offspring inherit an X chromosome from each parent.

As a recessive X-linked genetic disorder, the mutation that causes hemophilia is passed to offspring via the X chromosome. Hemophilia is more common among male children, as they only inherit one X chromosome, which means that they will develop symptoms of hemophilia if that chromosome carries the mutation.

Because the condition is recessive, the inheritance of one abnormal X chromosome does not usually cause symptoms in females because they usually also inherit another normal X chromosome. These females are then classified as carriers of the disease and can pass on the mutation to male offspring, even though they do not develop symptoms themselves. Technically, a female can develop hemophilia if she is born to a female carrier and a man affected by hemophilia, but this is very rare.

A female who carries a mutation for hemophilia has a 50% chance of passing the X chromosome that carries the mutation to her male offspring. The chance of her passing on the normal X chromosome that is not affected by this mutation is therefore also 50%.

Although hemophilia runs in families, there is occassionally no family history of the condition when a child is born with it. On the other hand, there are cases where female carriers are identified but male offspring are not affected. In about one third of cases, the child born with hemophilia is the first family member to develop the mutation.

What is hemophilia?Play

Genetic testing

Genetic testing and genetic counselling are available for couples with a family history of hemophilia who may want to determine how likely it is their child would be born with the condition. Genetic analysis of the FVIII gene identifies a mutation in up to 98% of people who have hemophilia A, while analysis of the FIX gene identifies a mutation in over 99% of those who have hemophilia B. Tests can also be performed to check for the gene during pregnancy using either amniocentesis or chorionic villus sampling.

Genetic research

Geneticists have been trying to develop a gene therapy for hemophilia A and the results have so far been encouraging. The long-term safety of gene therapies is still being carefully examined, but researchers hope that a genetic cure for the condition will eventually be available.

References Further Reading

Types Of Hemophilia / Haemophilia - Medical News Today

<?Php require_once "structure/framework/head/head_top.Php"; ??>Types of Hemophilia / Haemophilia<?Php $categoryID = 102; $subsectionID = 17; $subpageID = 2; $articleCategoryURL = "blood/"; $usefulLinkQueryString = isset($articleCategoryURL)?"?C=".Substr($articleCategoryURL, 0, -1):""; require_once "structure/framework/head/meta_pages.Php"; require_once "structure/framework/main/info/static_info_default_top.Php"; // ################################ ??>

knowledge center home » hemophilia » all about hemophilia » types of hemophilia

Hemophilia A and Hemophilia B

There are two main types of hemophilia - Hemophilia A (due to factor VIII deficiency) and Hemophilia B (due to factor IX deficiency). They are clinically almost identical and are associated with spontaneous bleeding into joints and muscles and internal or external bleeding after injury or surgery.

After repeated bleeding episodes permanent damage may be caused to the joints and muscles that have been affected, particularly the ankles, knees and elbows.

Approximately 1 in 5,000 males is born with Hemophilia A, and 1 in 30,000 males is born with Hemophilia B. Hemophilia affects people of all races and ethnic origins globally. The conditions are both X-linked and virtually all sufferers of hemophilia are males. Female carriers may also bleed abnormally, because some have low levels of the relevant clotting factor.

People with hemophilia have a genetic mutation in the affected gene on the X chromosome, which results in reduced production of Factor VIII or IX and creates a bleeding tendency, because coagulation takes much longer than normal, thus making the clot weak and unstable

Approximately one third of patients with hemophilia have no family history of the disease, either because of new genetic mutations, or because previous affected generations either had daughters (who were carriers) or sons who died in early childhood from hemophilia or any other cause or who were not affected.

<?Php ### MNT adverts included code ### if((!$glob_userMobile($glob_userMobile && $glob_responsiveOverride))){ //Desktop $adPositionSlotName = "MNT_DLB1"; //Numbers might be different, up to MNT_DLB3 include "structure/framework/adverts/mnt_leaderboard.Php"; }else{ //Mobile $adPositionNumber = 1; //Numbers might be different, up to 5 include "structure/framework/adverts/mnt_mrec.Php"; } ??>Acquired hemophilia

This is very rare. The patient develops the condition during his/her lifetime and it does not have a genetic or heritable cause. It occurs when the body forms antibodies that attack one or more blood clotting factors, (usually factor VIII), thus preventing the blood clotting mechanism from working properly. Patients may be male or female and the pattern of bleeding is rather different from that of classical hemophilia, the joints being rarely affected. The disorder is particularly associated with old age and occasionally complicates pregnancy.

<?Php // ################################### // Sidebar and Footer Content // ################################### include "section_bottom.Php"; require_once "structure/framework/main/info/static_info_bottom.Php"; // ################################### ??>

What Causes Hemophilia? What Are Chromosomes? - Medical News Today

<?Php require_once "structure/framework/head/head_top.Php"; ??>What Causes Hemophilia? What are Chromosomes?<?Php $categoryID = 102; $subsectionID = 17; $subpageID = 3; $articleCategoryURL = "blood/"; $usefulLinkQueryString = isset($articleCategoryURL)?"?C=".Substr($articleCategoryURL, 0, -1):""; require_once "structure/framework/head/meta_pages.Php"; require_once "structure/framework/main/info/static_info_default_top.Php"; // ################################ ??>

knowledge center home » hemophilia » all about hemophilia » causes of hemophilia

People with hemophilia are born with it. It is caused by a fault in one of the genes that determine how the body makes blood clotting factor VIII or IX. These genes are located on the X chromosome.

To understand how hemophilia is inherited, it is important to learn about chromosomes.

What are chromosomes?

Chromosomes are blocks of DNA (deoxyribonucleic acid). They contain very detailed and specific instructions that determine:

How the cells in a baby's body develop.

What features the baby will have, including, for example, hair and eye color.

Whether the baby is male or female.

In humans there are 23 pairs of chromosomes, including the sex chromosome pair. There are two types of sex chromosome:

The X chromosome

The Y chromosome

All humans have a pair of sex chromosomes:

Males have an X + Y pair

Females have an X + X pair

NB Females do not have any Y chromosomes.

What chromosomes do we inherit from our parents?

A Male inherits his

X chromosome from his mother

Y chromosome from his father

A Female inherits

One X chromosome from her mother

One X chromosome from her father

She does not inherit both X chromosomes from her mother. She has no Y chromosomes.

How can we calculate the risk of hemophilia in offspring? <?Php ### MNT adverts included code ### if((!$glob_userMobile($glob_userMobile && $glob_responsiveOverride))){ //Desktop $adPositionSlotName = "MNT_DLB2"; //Numbers might be different, up to MNT_DLB3 include "structure/framework/adverts/mnt_leaderboard.Php"; }else{ //Mobile $adPositionNumber = 2; //Numbers might be different, up to 5 include "structure/framework/adverts/mnt_mrec.Php"; } ??>

(Before reading on, remember that the faulty gene is never on the Y chromosome. If it is present, it will be on the X chromosome.)

Female (X + Xfaulty) is a carrier, but does not have hemophilia. The "good" X chromosome allows the production of enough clotting factor to prevent serious bleeding problems.

Male (Y + Xfaulty) will develop hemophilia and can pass it on.

If the father has hemophilia and the mother has no faulty gene (is not a carrier):

Father (Y + Xfaulty). Mother (X + X).

There is no risk of inherited hemophilia in their sons because boys will inherit their X chromosome from the mother, not the father (they inherit the father's Y chromosome only, which does not have the faulty gene).

All the daughters will be carriers but will not develop hemophilia although they will inherit the father's X chromosome, which has the faulty gene. However, their maternal X chromosome, which does not have the faulty gene, usually allows the production of enough clotting factor to prevent serious bleeding problems.

If the father does not have hemophilia and the mother has a faulty gene:Father (Y + X). Mother (X + Xfaulty).

There is a 50% chance that sons will develop hemophilia because:

There is a 50% risk that a son will inherit his mother's Xfaulty chromosome, plus his father's Y chromosome - he will have hemophilia.

There is a 50% chance he will inherit his mother's "good" X chromosome, plus his father's Y chromosome - he will not have hemophilia.

There is a 50% chance that daughters will be carriers, (but no chance of developing hemophilia), because:

There is a 50% chance she will inherit her mother's Xfaulty chromosome, making her a carrier.

There is a 50% chance she will inherit her mother's "good" X chromosome, which would mean she would not be a carrier.

Search This Blog

Congenital Hearing Loss