Are super males "violent demons" and super females "stupid beauties"?

Review expert: Mao Xinmei, Chief Physician of Pediatrics, Ningxia Women and Children’s Hospital, Peking University First Hospital

Recently, with the popularity of some film and television works, children with super male syndrome shown in the films often show violent tendencies, mental abnormalities and other problems. This made many people pay attention to the XYY group for the first time, and caused everyone, especially pregnant women, to have anxiety and ethical thinking about carrying an XYY fetus.

In the movie "Wade Through the Angry Sea", Li Miaomiao is a super male syndrome source | Movie stills

Super male syndrome is a genetic disease caused by chromosomal abnormalities . Patients often show impulsiveness, irritability, strong aggressiveness, violence and other problems. In addition, another genetic disease that has caused heated discussions is super female syndrome, in which patients are accompanied by mental retardation, developmental defects and other problems.

So what are the causes of super-androgenic syndrome and super-female syndrome? What are the clinical manifestations of these two symptoms? Are the rumored characteristics true?

Why do super male syndrome and super female syndrome occur?

In fact, this is caused by abnormal chromosome behavior. Normal people have 23 pairs (46) of chromosomes, including 22 pairs (44) autosomes and 1 pair (2) sex chromosomes (XX/XY), with the chromosome composition of 44+XX (female) or 44+XY (male). The spermatogonia or oogonia in the human body develop through meiosis to form mature sperm or egg cells. During meiosis, the abnormal movement of sex chromosomes will cause abnormal chromosome composition of the cells produced by division, forming 44+XYY type super male syndrome patients and 44+XXX type super female syndrome patients. The normal meiotic process is as follows.

Spermatogonia meiosis process Source: iknow-pic.cdn.bcebos.com

Oogonia meiosis process Source: file.zhuangpeitu.com

During the process of cell meiosis, chromosomes move randomly to the two poles of the cell under the traction of the spindles on both sides of the cell. When this random process is abnormal, the chromosomes will not move normally to the two sides of the cell, and the two sex chromosomes that should have moved to different sides will move to the same pole of the cell.

The formation of super male syndrome is that during the process of spermatogonia with sex chromosomes composed of XY undergoing meiosis to become sperm cells, the two Y chromosomes produced after replication move to the same side of the cell. Normally, two sperm cells containing Y chromosomes should be formed, but due to the abnormal chromosomes, one contains YY and the other does not have sex chromosomes. When the sperm cells develop into mature sperm and combine with the egg cells containing X chromosomes formed by normal meiosis, super male individuals with sex chromosomes composed of XYY will be produced.

Abnormal chromosome movement may also occur in oogonia. The formation of super-female syndrome is that during the meiosis of oogonia with a sex chromosome composition of XX to form oocytes, the two X chromosomes produced after replication move to the same side of the cell. Normally, two oocytes containing X chromosomes are formed, but due to the abnormal chromosomes, one oocyte containing XX and one oocyte without sex chromosomes are formed. When the oocyte matures and combines with the sperm containing X chromosomes formed by normal meiosis, a super-female individual with a sex chromosome composition of XXX is produced.

Therefore, both super-male syndrome and super-female syndrome are caused by the abnormal movement of the sex chromosomes of one of the patient's parents. The movement of chromosomes during meiosis is a random process and has nothing to do with the quality of genes . Therefore, from a biological point of view, there is no genetic determinism that someone is born a "devil" or a "stupid beauty".

Is it possible to live a normal life with these two syndromes?

During meiosis, the probability of abnormal chromosome movement is very small. The proportion of patients with super male syndrome in the social population is one in a thousand . Medical research shows that most of these patients are fertile, while a few have incomplete sexual development and sperm production disorders.

This genetic abnormality of XYY has been widely studied by geneticists. In various news media reports, carriers of XYY chromosomes were also considered to have characteristics such as tall stature, bad temper, and violent tendencies. However, in 2015, two scholars published a paper in an authoritative journal pointing out that in all the studies related to XYY in the past few decades, the only characteristic that can be confirmed to be clearly related to the XYY genotype is height that exceeds that of ordinary people . It is speculated that this may be the result of overexpression of Y-related genes. There is one more Y chromosome than normal people, and the genes on the Y chromosome in the body are twice as many as normal people. The related genes may be overexpressed, causing the patient to have characteristics such as tall stature. In other words, personality traits such as violent temperament and violent tendencies are not directly related to the XYY genotype . There is no evidence in existing studies that can directly prove that XYY genotype carriers will definitely have violent tendencies or violent personality traits .

Chromosome expression of patients with hyperandrogenic syndrome Source: bkimg.cdn.bcebos.com

However, the current medical textbooks have already regarded the view that this genetic abnormality leads to violent and criminal tendencies as wrong. The formation of each person's personality is influenced by multiple factors such as family environment, education and living environment. The selective expression of genes in biology is also the result of the combined effects of genetic genes and the environment. Therefore, it is inappropriate to simply and crudely link patients with super male syndrome with violent crimes and to think that chromosome type can determine personality.

Patients with super-female syndrome have clinical manifestations such as growth retardation, neuropsychiatric disorders, decreased fertility, increased susceptibility to autoimmune diseases, and neuropsychiatric disorders, which increase the risk of cognitive defects. Although some people call super-female patients "dumb beauties", in fact, super-female girls generally do not have obvious differences in appearance from normal girls. Unless both parents are good-looking, super-female girls will not be extremely good-looking. On the contrary, some patients may show cognitive defects, and may have wide eyes and small heads.

In general, most patients with super-androgenic syndrome and super-female syndrome can lead a normal life except for possible fertility disorders, cognitive disorders and mental problems.

How to prevent or treat it?

When pregnant women undergo prenatal testing, they can use amniocentesis and other testing techniques to check the chromosome karyotype of the fetus. If the fetus is detected to be a patient with super male or super female syndrome, the doctor needs to combine multidisciplinary knowledge such as genetics, psychology, and clinical manifestations to provide genetic counseling and risk assessment to the parents.

It is recommended that pregnant couples consider the maternal age and gestational age, their own age and history of infertility, the family's economic and social support, and their own acceptance of the possibility of fetal disability before deciding whether to continue the pregnancy. If the pregnant woman and her family choose to continue the pregnancy, they need to closely monitor the fetus with super-female or super-androgenic syndrome. After the child is born, the parents need to cooperate with the doctor to monitor the child's growth and development, and carry out necessary rehabilitation training and intervention treatment as soon as possible if there is a problem.

If super-male patients are detected to have infertility symptoms when they grow up, they can make their spouse pregnant through assisted reproductive technology . However, for the safety of offspring, it is recommended to conduct regular prenatal examinations and chromosome karyotype examinations on the offspring to ensure that the chromosome type of the offspring is normal. Super-female patients may experience varying degrees of amenorrhea or irregular menstruation. Women with normal reproductive system development can give birth, but patients with abnormal reproductive system development cannot give birth.

Source: pixabay

In general, super male syndrome and super female syndrome are two types of chromosomal abnormalities, similar to other chromosomal genetic diseases such as Turner syndrome (44+X) and Klinefelter syndrome (44+XXY), which are caused by abnormal chromosome movement. Patients may experience fertility problems, cognitive impairment, and may be more susceptible to mental illness, but they can also lead a normal life through modern medical means.

The patient's personality formation is determined by many factors such as the growth environment and personal experience. The individual's clinical manifestations are also produced by the selective expression of genes and the environment, and are not determined solely by genotype.