Genetic diseases and Chromosome testing, embryo screening
Chromosome screening for embryos is a high technology. Nowadays, new technologies are used to help with the analysis. It helps screen for embryonic abnormalities before implantation for faster and more accurate results, and can also increase the chances of pregnancy.
What is a chromosome?
Chromosomes are the genetic code that is located inside the nucleus of a cell (the cell is the smallest part of a person’s tissue), forming a pagan-like pair that controls the functioning of the cell, and the cell controls the functioning of the organs. Each person’s genetic characteristics are determined by their genes, which are the small parts of the genetic code on each pair of chromosomes. Each gene controls the formation, and function of cells, and determines the humanity of each person differently. There are 23 pairs divided into 22 body chromosomes and 1 pair of gender chromosomes. If it is a chromosome, XX means female, and the chromosome XY means male.
egg and sperm cells in each There is only one leg of a chromosome. When the mother’s egg and father’s sperm come together to form an embryo Thus, the chromosomes from the mother and father come together to form a pair of darts in the child. In the end, the genetics will be developed into individual genetics. This genetic trait is determined by each person’s genes that control their creation. cell function It is what defines a human being to stand out differently among individuals, including skin color, eye color, hair color, height, blood type, intellectual abilities, and physical development. Therefore, each person is different. Even siblings with cells from the same father and mother Each person must also develop their own genetics. Therefore, the brothers who crawled together were not the same.
If the division of germ cells is normal Children who are born will have a face that has been inherited from their father and mother. They have the same intellectual and physical abilities as normal children. But in the process of germ cell division Sometimes there may be a wrong division. Chromosomal abnormalities can be caused by a number of factors. One of the main causes is a mistake in the germ cell division process. The older the woman The chances of a mistake are even higher. Makes the risk that children born may be incomplete. They have inferior intellectual abilities and develop slower than normal children. Therefore, the examination of chromosomal abnormalities before the implantation of the embryo will help to make decisions about the pregnancy of the spouse easier. At present, there are new technologies to help in the analysis for faster and more accurate results.
How does the pre-implantation genetic disorder affect?
In addition to the risk of having a child with genetic disorders that affect the development and life of serious problems in the future. This genetic disorder also affects embryo implantation in the mother’s womb. reduce the chance of pregnancy It was found that mothers who conceived at an older age were more likely to find embryo abnormalities in chromosomal mutations. lower the chance of pregnancy some people experience recurrent miscarriages caused by chromosomal abnormalities in the embryo. These at-risk mothers need to be informed of embryonic abnormalities in order to make decisions together with their physicians. or in cases where the disorder is a genetic disease caused by a gene mutation. Being diagnosed in a parent with the possibility of passing the disease on to their offspring is a preparation for the family to accept the child to be born with a genetic disorder. Therefore, if the mother is in a group that is at risk of developing such disorders. Families who have received infertility counseling using in vitro fertility (IVF) or families with a history of inherited serious genetic disorders. It is highly advisable to undergo genetic screening and diagnosis before implantation to increase the chances of pregnancy. and have normal children free from genetic disease
genetic disease In a general sense, it is a disease that is transmitted from parent to child. The nature of the disease can be caused by two factors: chromosomal mutation or gene mutation.
chromosomal mutations can be classified into two forms: An abnormal number of chromosomes, such as an increase or decrease from the normal number of an entire chromosome, such as Down syndrome (trisomy 21) with one extra pair of chromosomes 21, or Turner syndrome (monosomic X) with an X chromosome. One bar is missing. Another pattern is Chromosome abnormalities include the absence of a chromosome fragment (deletion) and an increase in some chromosome fragments. (duplication) Alternating positions of different chromosome fragments. (translocation) and inversion of the same chromosome (inversion), which this group of abnormalities has a variety of clinical symptoms. And there are many related diseases.
gene mutation It is an abnormality caused by a mutation in the location of a specific gene. which controls some aspects of the body such as thalassemia This is a mutation in a gene that makes proteins involved in the functioning of red blood cells, for example.
Major genetic disorder
Down’s syndrome is a disorder caused by chromosomal abnormalities. There is an extra pair of chromosome 21, 1 stick from the normal 2 bars. It may also be caused by the translocation of the chromosomes, which the characteristics of children with Down syndrome have small heads and diagonal eyes. flat nose, protruding tongue, small mouth, short hands, and may have congenital diseases such as congenital heart disease intestinal obstruction thyroid deficiency, etc. This disease is often found in mothers who are pregnant at an older age.
Edwards syndrome is caused by an 18th chromosome pair disorder. One stick causes cognitive disorders, cleft lip, and cleft palate in the child. Fingers twisted and clenched together, a disease that kills children at a young age.
Color blindness is often a congenital disease and is more common in males than females. The symptom of people with this disorder is the inability to differentiate between green and red. or blue and yellow It will happen to both eyes. and cannot be treated
Hemophilia is a bleeding disorder in which the blood does not stop or clot easily due to a lack of a substance that causes the blood to clot. which is caused by an x chromosome error and is more common in males
Thalassemia is caused by a genetic abnormality that prevents normal hemoglobin production. The initial symptoms are similar to those of children with anemia, such as pale skin, yellow skin, easy tiredness, and slow growth. Dark urine, etc., treatment will be done by giving blood. and stem cell transplants from others.
Leukemia is also known as leukemia. It is a disease caused by the bone marrow producing an abnormal amount of white blood cells. And the white blood cells produced are not effective in resisting pathogens. therefore getting sick with frequent fevers The symptoms shown are high fever and chronic cold. Dizziness, weakness, paleness, etc. Some people may have severe symptoms that can lead to death. The treatment can be done with antibiotics. Alternatively, chemotherapy may be used to restore the bone marrow to normal function.
Why examine embryonic chromosomes?
- To know the abnormalities of the embryo before implantation. Reduce fetal abnormalities that may lead to miscarriages in the future.
- Reduce the rate of abortion or termination of pregnancy from an embryo with abnormalities.
- 100% screening for genetic diseases
- Healthy larvae can be selected.
- The chances of getting pregnant are 60-80 % higher.
- Reduces the transmission of hereditary diseases from generation to generation.
- PGT examination has an accuracy of up to 99%.
- Reduce the waiting period for pregnancy.
Analysis of embryonic chromosome abnormalities It uses genetically engineered technology to identify abnormalities in embryonic chromosomes and complete embryonic chromosome screening. This should be consulted by a qualified doctor.
Pre-implantation genetic selection (PGT) is an analysis of genetic diseases in an embryo before it can be reinserted into the uterine cavity.
This method was developed to select embryos with genetic material abnormalities, such as detecting abnormal chromosome counts by a method called PGT-A, used to detect abnormalities at the gene level by the PGT-M method, and to detect abnormal chromosome structure rearrangement by the PGT-SR method.
Formerly known as pre-implanted genetic disorder screening and diagnosis (PGS), it is a genetic analysis method that is a step in the IVF process. (IVF/ICSI) to increase the chances of a complete pregnancy. This is especially true in older females, where more than 50% of embryos are found to have abnormal chromosome counts, and egg cells with a higher or excessive number of chromosomes are often found than usual. Aneuploidy can cause Down’s Syndrome in infants. Embryo chromosome screening can therefore improve the chances of a successful pregnancy.
It was previously known as the Pre-Implantation Embryonic Single Gene Mutation Diagnostic Test (PGD), which was designed for patients at risk of inheriting genetic diseases caused by single-gene disorders. (monogenic mutation) to the child. Analysis and detection of single-gene abnormalities resulting in mutations by the method PGT-M is a step in the IVF process. Ivf/ICSI reduces the risk of giving birth to children with genetic disorders.
PGT-SR (Chromosome Structure Shuffle Detection)
Structural rearrangement is a chromosomal anomaly that occurs as a result of alternating chromosome fragments without increasing or decreasing genetic material, which is called equilibrium status. Reciprocal translocation results in a high probability of producing germ cells that contain incomplete or partial genetic material. PGT-SR reduces the rate of miscarriage from having an unbalanced chromosome and increases the chances of embryo pregnancy.
In the process of IVF, When the embryo is raised to the mature stage ready to be In the IVF process When the embryo is cultured to the full maturity stage, ready to be implanted, or Blastocyst stage (5th day of embryo culture), more than 100 embryonic cells are formed, consisting of the inner cells. The cell mass produced will develop into a baby, and the outer cell (trophectoderm) will develop into the placenta. A small number of overgrown cells are biopsied for genetic analysis. Without affecting the development of the embryo and does not harm the cells that will develop into the baby. Cells are sampled and then extracted and enriched with DNA for Next Generation Sequencing (NGS), the most advanced technology in sequencing the entire genetic material in a cell. (Genome) This analysis process can be used to detect 24 chromosomes, including 22 non-determinant chromosomes (autosome) and two sex chromosomes (X and Y), with high accuracy (99.9%). Examination of chromosome deletions/duplications (Extra or missing chromosome fragments) with high resolution clearly. The embryo with normal chromosomes will be screened before the embryo is implanted into the uterus implanted, or during the Blastocyst stage (the 5th day of embryo rearing), more than 100 embryonic cells are created, consisting of The inner cell mass that is created will grow into the baby, the outer cell (trophectoderm) will grow into the placenta. A small number of overgrown cells are then biopsied for genetic analysis. It does not affect the development of the embryo and does not harm the cells that will develop into the baby in any way. The cells sampled are then extracted and added to the genetic material (DNA) for next-generation sequencing (NGS) analysis, the most advanced technology to determine the base sequence of all genetic material in a cell. The analysis process can be used to examine all 24 chromosomes, including 22 non-autosome chromosomes and two sex chromosomes (X and Y) at high accuracy (99.9%). With clearly high resolution. Embryos with normal chromosomes are screened before further implantation of the embryo into the uterine cavity.
- Check the patient’s background check and the genetic test record and may request additional tests to assess whether we are able to detect such genetic abnormalities in the embryo.
- In consultation with our team of genetic consultants, we will advise on the benefits and limitations of testing and analysis by way. PGT-M depends on the condition of each patient, which varies. The test requires a sample of the saliva of the parents or in some cases requires that of a sibling or relative.
- IVF/ICSI after completion of the preparation process Our specialist doctors will inform patients to begin ivf treatment process to create quality embryos.
- Embryo culture and embryo biopsy to detect genetic diseases The embryos are raised under controlled conditions until the blastocyst stage on the 5th or 6th day of culture, where a small number of cells from the trophectoderm that will grow into the placenta are biopsied for further analysis of genetic material.
- Genetic testing The embryo’s genetic material is analyzed to detect specific mutations by analyzing for this difference caused by a single nucleotide type change. The analysis of the number of chromosomes in embryos, it is monitored by NGS technology.
- Transfer of embryos with non-diseased genetically validated results and a normal number of chromosomes will be screened before further implantation of the embryo into the uterine cavity.
Advantages of PGT-A
- Increases the chances of a healthy pregnancy.
- This is because preimplantation genetic abnormalities screening and diagnosis (PGT-A) improves pregnancy success rates. Thus, it is a way to reduce the cost of IVF/ICSI by reducing the number of treatment cycles until a successful pregnancy.
- Increase the chances of embryo implantation.
- Reduce the risk of miscarriage.
PGT-A is suitable for
• Women over 35 years of age due to the high-risk rate of giving birth to children with abnormal chromosomes
- Spouses who have had IVF treatment before but were not successful
- Couples with a history of more than 2 miscarriages before 12 weeks times
- Male or Female patients with a family history of chromosomal abnormalities
PGT-M is suitable for
- Spouses who are a carrier of a genetic disease or have had a child with a genetic disease
- Autosomal recessive inheritance. A person with the disease must have two abnormal alleles inherited from both parents. For example, thalassemia. If there is only one abnormal gene, the allele is known as a carrier of the disease. will have normal health but can pass on the abnormal gene to future children
- Autosomal recessive heredity Those with the disease must have 2 alleles of abnormal genes derived from both parents. For example, thalassemia. If there is only one abnormal gene, allele. It is called a carrier of the disease, it is healthy and normal but can transmit abnormal genes to future children.
- X-linked inheritance of Muscular Dystrophy, Colorblindness, and Other Conditions
Next Generation Sequencing Chromosome Abnormalities Examination (NGS)
Before embryo implantation, chromosomal abnormality testing is commonly used. This is due to the fact that it increases the likelihood of a successful pregnancy. This is due to the fact that many couples have had IVF failures for unknown reasons. Experts predict that more than half of IVF failures will be unknown. Explain that it may be due to the embryo’s quality. Incomplete division or visible genetic abnormalities.
Therefore, the examination of chromosomal abnormalities before the implantation of the embryo by specialist doctors and scientists will definitely help increase the chances of a successful pregnancy. Because it will be able to examine deep to the chromosome level. that there are any pairs of chromosomes that are abnormal until unable to grow any further It also includes testing the last pair of chromosomes that can determine whether the embryo is female or male.