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Discover more about the World Hemophilia Day

Discover more about the World Hemophilia Day

April 17, 2020 is World Hemophilia Day and communities stay together to support their mission. Let's get to know more about it.

What is Hemophilia?

Hemophilia is a hereditary genetic disease, which impairs the normal clotting process. As a result, the affected patient is subject to prolonged bleeding, even after trivial traumas or skin cuts.

In most cases, the origin of hemophilia is a genetic mutation of the sexual chromosome X, transmitted from parents to their children. Like Duchenne muscular dystrophy or colour blindness, therefore, hemophilia also belongs to the group of so-called hereditary sex chromosome-related diseases.


The causes of Hemophilia

The cause of hemophilia is a genetic mutation of the sexual chromosome X, which determines the deficiency of one of the coagulation factors.

The coagulation factors. Patogenesis

The coagulation factors are biomolecules (proteins, enzymes and cofactors), produced in part by the liver and circulating in the blood and ther are only functional for their purpose if they are all present.
The reason is simple. They are activated in a chain ("cascade mechanism"), one after the other. In other words, each factor acts as a trigger for what follows it. Therefore, if one factor is missing or deficient, the following ones, which depend on it, will not be triggered or will be activated slowly. All this results in a coagulative defect.

GENETICS

Why does hemophilia mostly affect the male sex?
The X chromosome mutation, which determines hemophilia, is recessive. This means that the woman, with two X chromosomes, manifests the disease only if both of her sex chromosomes are mutated (a very remote possibility); in fact, when only one X chromosome is mutated, the other healthy one compensates for the deficiencies of the first one and produces the missing coagulation factor itself.
Vice versa, in man, the X chromosome is only one (the other is the Y chromosome) and one of its mutations is fatal and without alternatives. Consequently, the coagulation process lacks, in an irremediable way, a fundamental component.

 

Hemophilia and Heredity

How does the X chromosome transmission between parents and children occur? 

If the mother is a healthy carrier
The union between a woman with only one changed X chromosome (therefore called a healthy carrier) and a healthy man can have the following consequences:
  • Male children have the same probability (50%) of being born healthy or ill. The Y chromosome inevitably comes from the father; consequently, the X chromosome comes from the mother. If it is the changed one, the child will be born with the disease.
  • Female daughters have the same probability (50%) of being born healthy or completely healthy. They inherit the healthy X chromosome from their father. The other X chromosome, inherited from the mother, may be sick or healthy.

If both parents have a changed X chromosome

Since hemophilia is a disease compatible with life, a sick man can have children. His union with a healthy carrier woman can give birth to:

  • Male children with the same probability (50%) of being born healthy or sick. It is like the case, where there was only the healthy carrier mother of the disease. It is the maternal X chromosome that determines the state of health of the male child, because they inherit only the Y chromosome from the father.
  • Female daughters with the same probability (50%) of being born healthy or sick carriers. They definitely inherit a changed X chromosome from their father. The other chromosome, the maternal chromosome, can be either healthy or mutated.

If only the father is sick

In this case, his union with a healthy woman has two consequences:

  • The male children are all born healthy because the maternal component is missing.
  • Female daughters are all born healthy because they all receive the changed X chromosome from their father.

Types of Hemophilia

There are three types of hemophilia, based on the coagulation factor involved:

  1. Hemophilia A, where the deficient coagulation factor is factor VIII.
  2. Hemophilia B, where the deficient coagulation factor is factor IX.
  3. Hemophilia C, where the deficient coagulation factor is factor XI. This type is an autosomal genetic disease, since the genetic abnormality resides on autosomal chromosome 4.

About genetics and Hemophilia

Hemophilia can be both mild and severe but in most cases it has a genetic origin.
It can manifest itself in childhood but also during the rest of life. It is caused by a mutation on the X chromosome in the gene that provides instructions for making the factor that  synthesizes the proteins needed to form blood clots. This mutation can lead to the loss of the function of the proteins or to a lack of the proteins themselves. For the fact that the gene is located on x chromosome only males are ill, females are healthy carriers for the mutation. Females can also have some symptoms and they pass the mutations to the prole. 

Acquired Hemophilia is another form of disorder that is not caused by genetic mutations but by abnormal bleeding into various tissues. It is caused by an autoantibodies response in which is attacked by coagulation factor VIII. This kind of response is associated with cancer or immune system disorders, but sometimes the cause is unknown. Hemophilia occurs in about 1 of every 5,000 male births. 

Hemophilia A is caused by a mutation in gene F8, that gene is responsible for making the protein coagulation factor VIII. Instead the gene F9 produced the coagulation factor IX  and a mutation in this gene can cause hemophilia B. 

 

Advantages of getting the Whole Genome Sequencing for Hemophilia

There are specific blood tests for hemophilia that evaluate the blood clotting ability or that investigate the specific clotting factors such as factor VIII and factor IX. Those tests are based on the observance of clotting time and are useful only when the patients are experiencing health problems.

But it is important to do a genetic test because of various reasons:

Because of it is possible that in a patient hemophilia occurs not only at childhood, is important to prevent this pathology with a DNA test;

It is also important to know if a woman is a carrier for the pathology, to evaluate the possibility of passing the mutant gene to the prole;

It is important to patients with hemophilia to know which gene is mutated because mutation in gene F8 causes hemophilia A and mutation in gene F9 causes hemophilia B.

For prevention the DNA test is the best way to know if you have a pathology of you are a carrier for a mutated gene.

 
About World Hemophilia Day 

World Hemophilia Day is held annually on April 17 by the World Federation of Hemophilia (WFH). It is an awareness day for hemophilia and other bleeding disorders, it was started in 1989 and April 17 was chosen in honor of Frank Schnabel's birthday, founder of the WFH.

Every year the theme of World Hemophilia Day changes and now, in 2020, it is “Get+involved”. It’s a call to action for everyone to help drive the WFH vision of “Treatment for all” at the community and global level. All the communities want to encourage you to help increase the awareness of inherited bleeding disorders and the need to make access to adequate care possible everywhere in the world.

This landmark day also helps to illustrate the importance the WFH has developed to support the bleeding disorders community, from integrated care development training programs to ensure the local infrastructure and medical expertise are available to optimize and appropriately use donated products, to programs developed to greatly increase the diagnosis and treatment of people with bleeding disorders by closing the gap in treatment between developed and developing countries.

Dante Labs for World Hemophilia Day

Dante Labs decided to be involved in raising awareness of Hemophilia, together with the whole community. 

Our customer care service will be available to answer your questions and will help you understand the importance of genetic tests.

Wear blue and do not forget to Get+involved

Click here to learn more about Dante Labs DNA Tests and discover our Hematology report here.