Human beings have 23 pairs of 46 chromosomes. Each pair is from the father, and the other comes from the mother, which contains all the genetic information of the growth and development of the fetus.These 46 chromosomal design is precise and accurate with information. It is accurately translated through complex processes such as replication and separation during the combination of fine eggs to ensure the health of the child.
If the chromosomes passed to the child are one more, one less, one more, and one less, it will cause signal transfer errors, causing different degrees of malformations or defects during the fetal development.Tang’s syndrome is the most common chromosome disease.The reason is that the two 21 chromosomes from the father or mother did not break up when they broke up due to some reason. They walked into a cell together. Once this cell forms a fertilized egg, she obtains a chromosomes from the father or mother, the fetus, the fetus, the fetus, the fetus, the fetus, the fetus, the fetus, the fetusThe No. 21 chromosome became three, that is, 21 trilateral, and Tang’s syndrome occurred.
Donald Syndrome English is called DOWN ’s Syndrome, translated as" Tang’s syndrome ". It is named after the surname of British doctor John Langdon Down to commemorate him in 1866 to take the lead in a complete description of the facial features of such diseases.In the same way, 18 trimer syndrome, also known as Edward syndrome.The simple understanding is that the fetus No. 18 into trilateral, resulting in a series of malformations.
The incidence of Tang’s syndrome is about 1/700 ~ 1/1000.The occurrence of Tang’s syndrome is also related to the age of her mother.With the increase of age, the aging of the eggs is more likely to cause the No. 21 chromosome to be separated when separated, which increases the probability of the Tang’s syndrome in the fetus.For example, among the 35 -year -old pregnant women, the risk of fetal syndrome is 1/350, and the 45 -year -old pregnant women can rise to 1/25.But it is worth noting that the risk of Tang’s syndrome is not just for the existing family history or older mother.
In fact, Don syndrome is an occasional disease. Each healthy couple has the risk of childbirth chromosomal diseases. That is to say, any pregnancy may be pregnant with a fetus.A chromosomal disease with a high incidence and very serious hazards, so each pregnant woman needs to screen.(Beijing Tsinghua Chang Gung Hospital)
Source: Beijing 12320 is listening
