Chromosome abnormalities in test tube infants
IVF is a method of assisting pregnancy through in vitro fertilization. Its success rate is increasing, but there is still a risk of chromosomal abnormalities. Chromosome abnormalities refer to abnormalities in the structure, quantity or distribution of chromosomes in embryos or infants, which may lead to physiological and developmental disorders. The following four aspects will describe the chromosome abnormalities of IVF.
1. Common chromosomal abnormalities
Common chromosome abnormalities include Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), Patterson syndrome (Trisomy 13), etc. Down's syndrome is the most common chromosomal abnormality. There are three chromosomes in the 21st pair of patients, instead of two normal chromosomes. These abnormalities already exist in the embryonic stage, which may affect the normal development of the embryo.
In addition to the three common chromosomal abnormalities, there are other atypical chromosomal abnormalities, such as sex chromosome abnormalities (such as Turner syndrome, Klinefelter syndrome, etc.) and structural abnormalities (such as chromosome inversion, translocation, etc.). The incidence of these chromosomal abnormalities is low, but there are still some risks.
2. Diagnosis method of chromosome abnormality
The diagnosis of chromosomal abnormalities in test tube infants can be carried out by routine non-invasive prenatal gene testing, amniocentesis or chorionic biopsy. Noninvasive prenatal gene testing is a non-invasive method. By collecting fetal DNA from maternal blood for analysis, we can detect the risk of common chromosomal abnormalities. Amniocentesis and chorionic villus biopsy can obtain more accurate results by obtaining fetal cell samples for chromosome analysis.
In the diagnosis of chromosome abnormalities, accuracy and safety are very important factors. Therefore, in the detection of chromosome abnormalities, formal hospitals and professional medical teams should be selected, such as Peking Union Medical College Hospital, Children's Medical Center affiliated to Shanghai Jiaotong University, to ensure the accuracy of the results and the safety of the operation.
3. Risk factors of chromosome abnormalities
The risk of chromosomal abnormalities in IVF is affected by many factors. Age is the main risk factor, and the increase of female age will lead to a gradual increase in the risk of chromosomal abnormalities. Other risk factors include family history, prenatal genetic counseling, hypertension, diabetes, etc. In addition, in vitro fertilization technology itself may also have an impact on chromosomes, such as embryo screening before embryo transfer and thawing implantation of frozen embryos.
In order to reduce the risk of chromosomal abnormalities, a comprehensive genetic consultation and evaluation should be carried out during the diagnosis and treatment of IVF, and the families with chromosomal abnormalities should be screened. In addition, if there are high-risk factors, PGD or PGS can be considered to screen embryos without chromosomal abnormalities for transplantation.
4. Prevention and treatment of chromosome abnormalities
At present, there is no specific drug that can directly treat chromosome abnormalities. Prevention and treatment of chromosome abnormalities mainly depend on early diagnosis, genetic counseling and screening, and progress in assisted reproductive technology.
With the progress of science and technology, more accurate and safe gene editing techniques have emerged, such as CRISPR/Cas9, which provides a new method for preventing chromosome abnormalities. Gene editing for embryos with chromosomal abnormalities can repair chromosomal abnormalities and improve the success rate of IVF.
Summary
Chromosome abnormalities in test tube infants are a common problem. Common chromosome abnormalities include Down syndrome, Edwards syndrome and Patterson syndrome. The diagnostic methods of chromosome abnormalities include non-invasive prenatal gene detection, amniocentesis and chorionic biopsy. The risk factors of chromosome abnormalities are affected by many factors, such as age, family history and in vitro fertilization technology. In order to reduce the risk, comprehensive genetic counseling and evaluation are needed, and embryo gene testing is considered. At present, the prevention and treatment of chromosome abnormalities mainly depend on the progress of early diagnosis and assisted reproductive technology.
