According to Guangzhou Daily, Mr. Wang is 45 years old and has a son in his early years, but when the couple were trying to conceive and have a second child, Mr. Wang was found to have no sperm in his semen.
Is the firstborn son biological? The husband and wife were one angry and the other aggrieved.
After the paternity test, the test result showed that the child was Mr. Wang's biological son, so what is going on?
Experts advised Mr. Wang to undergo further examinations. Finally, after Mr. Wang's examination results came out, he found that it was originally a "ghost" with a microdeletion of the Y chromosome (the report suggested: AZF c region deletion).
It turns out that there are azoospermia factor (AZF) regions that affect spermatogenesis on the long arm of the Y chromosome, including three regions of AZFa, AZFb, and AZFc, and the deletion of these regions may lead to male oligospermia, weak sperm, and azoospermia.
Mr. Wang is a patient with AZF zone c deletion and semen quality declines progressively with age. When young, it may manifest as less weak sperm, and in some cases, it is also organic to make the woman conceive normally.
Why are the chromosomes good, say that they are lost, today the circle sister will take you to understand the chromosome microdeletion!
01How did the ancestral chromosomes be lost?
If random mutations in DNA are ignored, then all male Y chromosomes can be said to have been inherited from male ancestors thousands of years ago.
In other words, if your surname is Li, then you are likely to have the same Y chromosome as the famous Tang Taizong Li Shimin.
However, inheritance has inheritance tax, and errors are sometimes inevitable in the process of vertical transmission of chromosomes, and current research has found that Y chromosome microdeletions are the most common genetic factors that cause male spermatogenesis disorders.
Studies have found that most Y chromosome microdeletions are caused by new mutations, and some scholars have tracked the family lines of 44 pairs of fathers and sons and found that 82% of Y chromosome microdeletions are caused by new mutations.
There are also about 18% of patients due to vertical transmission of the father, and the Y chromosome microdeletion in such patients tends to expand during transmission, resulting in infertility in offspring.
That is to say, most of the Y chromosome deletions are accidental mutations, and a small part is inherited, and the more inherited it is, the more likely it is for the offspring to become infertile and eventually no longer have offspring.
At this time, did the male compatriots want to look up to the sky and sigh, originally thinking that the ancestral porcelain would bump, but did not expect that even the ancestral Y chromosome would bump, say lose it?
What are the manifestations of 02Y chromosome microdeletion?
Normal people have 23 pairs of chromosomes, including 22 pairs of autosomes and 1 pair of sex chromosomes. The difference between male and female sex is mainly determined by sex chromosomes, with women having two X chromosomes and men having one X chromosome and one Y chromosome.
There are many genes related to sperm development on the Y chromosome, and once these genes are missing, it will affect the spermatogenesis of men, which in turn affects fertility.
After reading the above content, do the sisters want their husbands to do this examination, after all, early detection and early treatment! Does everyone need to do this test?
Y chromosome microdeletion is an important cause of severe oligospermia or azoospermia in men, and is the second most genetic factor leading to male infertility, with a incidence second only to Kirschner syndrome.
The incidence of Y-chromosome microdeletions in the population is 1 in 4000, but it is significantly higher in infertile men, with a incidence of microdeletions ranging from 2% to 10% (or even higher). The frequency of Y-chromosome microdeletions in infertile men in China was 11.5%, which was at a high level.
That is to say, if the doctor diagnoses your husband as azoospermic or oligospermic, exclude obstructive factors, that is, non-obstructive azoospermia, high sperm malformation rate, unknown male infertility patients, and patients with habitual miscarriage of their wives are recommended for this examination.
Of course, there are also men with normal semen who have this problem, but it is not very common!
03What tests are needed to confirm the diagnosis?
After reading my above statement, do the sisters feel that they have a good idea of their man's condition, but after all, this is medicine, and it must be diagnosed by examination.
Some sisters said that both of our husband and wife have done chromosomal examinations, and no chromosomes have been found.
It should be emphasized here that ordinary chromosome examination cannot find Y chromosome microdeletions, and special testing is required.
The Y chromosome microdeletion was first detected in 1976 when scientists examined the Y chromosome of 6 patients with azoospermia and found that some regions of their Y chromosome were missing.
Therefore, this area is called azoospermia factor (AZF), and the region is specifically divided into three regions: AZFa, AZFb, and AZFc.
The available data show that patients with AZFa and AZFb deletion do not have sperm in their bodies, and can only be conceived through sperm from the sperm bank.
About 70% of such patients can obtain sperm through microsurgery and conceive the woman through IVF.
The Y chromosome test can be completed by drawing blood tests, and patients do not need special preparations such as fasting.
04What is the impact of microdeletion on future generations?
This we mentioned a little earlier, here is the system, to put it bluntly, the Y chromosome microdeletion in the vernacular is the trend of male sex weakening, until there are no offspring.
Y chromosome microdeletion is a disease that can be inherited through the Y chromosome, occurs only in males, and is passed down from generation to generation in families, theoretically occurring in boys, but the clinical manifestations or severity will vary.
Loss of the Y chromosome AZFa and AZFb regions does not produce offspring because sperm cannot be produced.
Deletion of the AZFc region of the Y chromosome can be born to their own children through IVF technology, and will not be inherited if it is a girl.
If it is a boy, then the father's micro-deletion of the Y chromosome can be passed vertically to the son, and even the deletion range will be expanded.
Therefore, you should really consider the sex of the baby before embryo implantation!
It is recommended that such patients do genetic counseling before family planning, and may consider third-generation IVF (pre-embryo transfer genetic diagnosis) to help pregnancy.
Third-generation test-tube technology selectively transfers female embryos, thereby avoiding the transmission of Y chromosome deletions to the next generation of boys.
05What factors can cause micro-deletions?
We said earlier that 80% is because of mutation, 20% is due to heredity, heredity cannot be changed, so how is the mutation caused, is there anything that can be remedied?
Now, in one of the largest studies of the phenomenon to date, an estimated 20% of more than 200,000 male samples from the UK biobank have lost some of their Y chromosomes.
By the age of 70, 43.6% of men develop this phenomenon.
This means that the older the age, the greater the risk of microdeletion, so the childbearing age of men is not without time limits.
A paper published in the journal Science showed that men who smoked for a long time had shorter Y chromosomes or even disappeared compared to non-smokers.
The experiment, conducted by researchers at Uppsala University in Sweden, surveyed three different groups of men in Sweden.
The researchers analyzed the Y chromosome in the participants' blood cells (probably because blood testing is a convenient way to detect it) and investigated their lifestyle habits, and came to some conclusions:
1. There is a strong correlation between long-term smoking and Y chromosome loss;
2. The degree of shortening of chromosomes is dose-dependent. Simply put, the more cigarettes you smoke, the more serious the shortening of the Y chromosome, and to a certain extent, the Y chromosome is lost.
In this way, smoking is likely to be a reason why sperm quality is becoming more and more deteriorating.
Sisters, don't stuff your head to get pregnant, don't be pregnant for a long time, quickly take your husband's little hand and go to the hospital, finding out the problem is the first step to solve the problem.
Although the Y chromosome microdeletion sounds terrifying, most of them can actually achieve the desire to have children through IVF!
As for those who are completely infertile, they can also end the purgatory of pregnancy preparation early and look for other solutions, we try to find a way, but by no means in vain without direction, come on!
For the record
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