Is it true that women do not suffer from hemophilia?

It is common that “royal disease” affects only men, and women can only be its carriers. We decided to check if such a belief is correct.

That hemophilia is an exclusively male disease, write in some medical reference books and on sites healthcare institutions. IN memo The official protocol for the treatment of this disease prepared by the Ministry of Health of the Russian Federation also does not say about the spread of hemophilia among women. In many Russian -language publications about this disease in Media And Blogs They mention the suffering from her Tsesarevich Alexei, who is believed to inherit hemophilia from his mother, and she from his grandmother, British Queen Victoria. However, about the manifestations of hemophilia in women in such texts Often nothing is said. The authors of the popular science articles.

Hemophilia is inherited violation Blood redistribution. Depending on which groups of substances (casualtime factors) are not enough for the body, hemophilia A is distinguished (caused by a lack of factor VIII) and hemophilia B (caused by a lack of factor IX). Also, hemophilia is sometimes called a deficiency of the XI blood factor, most often found in Jewish-ashkenes, however, its type of inheritance and clinical manifestations differ significantly from more common types A and B, therefore, it is not included in the modern scientific literature to hemophilia. Hemophilia is characterized by increased bleeding from the first days of life - subcutaneous, intermuscular, subfascial, retroperitoneal hematomas, bleeding from gums and nose, hemorrhages into internal organs, eyes, joints. They can occur both due to injuries or operations, and without them-due to the vulnerability of the walls of the vessels. Select Three degrees of hemophilia: Light (level of factor of viophability VIII or IX from 5% to 40% of the norm), average (from 1% to 5% of the norm) and heavy (less than 1% of the norm).

The idea of ​​hemophilia as a disease manifested exclusively in men probably arose precisely because of its prevalence Among the members of the ruling houses of Europe, the turn of the XIX - XX centuries. The manifestations of the disease were noticeable among the son of Nicholas II of Tsarevich Alexei, German, Spanish and other princes, but not their sisters or mothers. The common ancestor of the heirs was the British Queen Victoria. 

This phenomenon was later studied by genetics. It turned out that the production of the vilativity factor VIII and IX is encoded on the X chromosome. Since the men of the X-chromosome have only one (chromosomal set of XY), it is enough for them to inherit one damaged X-chromosome from the mother so that the factor is not produced in normal quantities, that is, hemophilia manifests itself. The chromosome set of women is XX, one chromosome is inherited from the mother, the second is from her father, that is, so that a woman is ill with hemophilia, she must get one damaged chromosome from both parents. However, until the middle of the last century Duration The lives of men suffering from this ailment were very low - young men with hemophilia on average survived only up to 20 years and in the vast majority did not manage to leave offspring. 

The situation has changed due to the development of replacement therapy methods. Now the life expectancy of men with hemophilia for only ten years below The average, therefore, the probability of the birth of their daughters who inherited the disease has grown. In 2023 in the world hemophilia They were sick approximately 400,000 men, ladder women were 1.6 times morethat is, about 640,000. If one of these 400,000 men meets one of these 640,000 women, their daughter will accurately receive the damaged X-chromosome of his father and with a probability of 50% of the same from the mother. The probability of this event seems low, however, in communities practicing related marriages, it higher. 

At the same time, only 70% of hemophilia cases Related With the inheritance of the mutation from parents. The remaining 30% is the so -called Sporadic Hemophilia, when a mutation in the genes occurs on its own. Such a change can occur with equal probability in both men and women, and their children can already inherit the damaged copy of the gene. It is likely that the queen Victoria arose It is sporadic hemophilia - at least there is no data indicating that her parents had problems with blood coagulation. However, such a mutation that happened to a woman usually does her not sick, but only a carrier, as was the case with Victoria, and then with those her daughters who inherited the damaged chromosome. 

However, carriers cannot be automatically attributed to people without problems with blood coagulation. It's all about Liionization X-chromosomes-a process named after the scientist Mary Lyon. So that two copies of the X-chromosomes in the body do not form twice as many corresponding genes than that of males, one chromosome in each cell “turns off”. How the choice is, scientists are not clear - most likely, the body does It is by chance. However, the distribution is almost evenly, that is, in about half of the cells of the female body “turned off” the maternal X-chromosome, and in half the paternal. If the equality is violated “in favor of” the mutated chromosomes, a woman manifests problems with blood coagulation. According to the European consortium on hemophilia issues, due to laionization on average in women carriers approximately 50% of the normal level of factor of coagulation. Moreover, if in men in therapy, hemophilia manifests itself when the level of factor of swimming falls below 40% of the norm, in women abnormal bleeding can occur when this indicator is between 40% and 60% (in this case usually They say About a symptomatic medium). 

It turns out that a woman can suffer from hemophilia, that is, suffer from a deficiency of the factor of swollenness, in three cases:

• if she is the daughter of a father, a patient with hemophilia, and a mother-ladder;
• If she inherited the damaged gene from one of the parents, and as a result of life-to-the-lionization, more healthy x chromosomes were “turned off” in her body;
• If it is born from healthy parents, but a spontaneous mutation occurred in its genome and, as a result of lifeization, more healthy X chromosomes are also “turned off” in her body.

By assessment The World Hemophilia Federation, in 2012 about 364,000 men with type A hemophilia, 97,000 men with type B hemophilia lived in the world and a little more than 359,000 women who suffered from abnormal bleeding associated with one of the three described paths of this disease. That is, men with hemophilia are not much more than women suffering from her (approximately 56% and 44%, respectively).

Hemophilia in women in comparison with men Combines A number of additional problems. Firstly, they experience more abundant and protracted menstruation-menorrhagia, which, due to significant blood loss, can lead to iron deficiency anemia. Abundant menstruation can push women to reduce social activity. In addition, they are susceptible to bleeding during ovulation and during the period before the onset of menopause, as well as bleeding into simple ovarian cysts, which requires emergency surgery. In some cases, women with hemophilia even have a hysterectomy. Secondly, pregnancy in women with hemophilia Coarded With an increased risk of life -threatening bleeding, both during childbirth and in the next weeks. However, usually women suffer From the light and medium forms of hemophilia, the heavy manifests itself mainly in men.

At the same time, obtaining adequate medical care for women suffering from this disease is difficult. Swiss pharmacological company Roche NotesWhat are usually excluded from important clinical studies-due to monthly fluctuations in hormones levels, it is difficult to test drugs on women. Therefore, many innovative treatment methods have been developed exclusively by male volunteers and approved by regulators only for them. 

Thus, to believe that hemophilia is exclusively male disease, and women can only be its carriers, is absolutely wrong. Firstly, a woman will suffer from hemophilia if she inherits one damaged X-chromosome from her father and mother. Secondly, about every third case of hemophilia was obtained as a result of a spontaneous mutation, and not with the genes of parents. Thirdly, even with one damaged chromosome, a ladder can suffer from abnormal bleeding, since due to the lionization process, about half of the healthy X chromosomes will be in a “turned off” state. As studies show, women with hemophilia are very few less than men.

Image on the cover: RAWPIXEL

Not true

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