Genetic determination of paternity/maternity (2 participants: child and intended parent)

This hormone is not detected in the body of a non-pregnant woman. But when pregnancy occurs, it is thanks to the analysis that it is possible to calculate the exact timing by week. In addition, a change in the level of hCG in the blood of the expectant mother is a signal about the presence of certain pathologies. So, low hCG can indicate conditions such as:

• post-term pregnancy;
• chronic fetoplacental insufficiency;
• intrauterine infection of the fetus.

If deviations from the norm are small, additional studies are prescribed.

HCG level: table

Conclusions:

Genetic testing for celiac disease is a good tool for a doctor if used correctly.

This examination should not be done by everyone.

These genetic characteristics are very often found in completely healthy people who will never develop celiac disease.

Small update:

Recently I came across an excellent video by Yulia Andreevna Dmitrieva, head of the Functional Center for Children with Celiac Disease (Moscow), about how things are not so simple with genetic tests and not every laboratory can give the correct conclusion. Also a very interesting topic with the incomplete molecule DQ 2 and DQ7. With these options, celiac disease is possible, but they are often not indicated in the reports. Explanation in the video around 18 minutes.

1, total, today

Decoding hCG indicators

During a normal pregnancy, hCG levels rise steadily, doubling every few days in the first trimester. The highest level of hCG in the blood is observed at 10-12 weeks, after which it gradually decreases and in the second half of pregnancy has an almost constant value. Elevated hCG may indicate the following conditions:

• multiple pregnancy (the result increases in proportion to the number of fetuses);
• diabetes mellitus in pregnancy;
• toxicosis, gestosis;
• incorrect determination of gestational age;
• a woman taking synthetic gestagens.

When the hCG calculator shows an increased result in a non-pregnant woman or man, and they do not take hCG tablets or injections, this can warn of such serious ailments as tumor diseases of the digestive system, kidneys, lungs, chorionic carcinoma, neoplasms on the testicles in men and on uterus in women.

High levels of hCG can be observed 4-5 days after termination of pregnancy. If after a mini-abortion the indicator does not fall, it means that the pregnancy continues.

Low hCG during pregnancy means either incorrect timing or other serious disorders:

• non-progressive pregnancy;
• ectopic pregnancy;
• fetal developmental delay;
• threat of miscarriage (if decreased by more than half);
• post-maturity;
• placental insufficiency;
• fetal death (in the second half of pregnancy).

Sometimes an hCG test shows a negative result. This hCG level occurs during ectopic pregnancy. But perhaps the study was simply done too early.

Disorders in the blood coagulation system

The blood coagulation system, or hemostasis, performs one of the most important functions in the human body. On the one hand, it protects against bleeding (the anticoagulant component of the system), on the other hand, it prevents (the coagulation component) the formation of thrombi (blood clots). Normally, the coagulation and anti-coagulation components of the hemostasis system are balanced, which allows the blood to remain in a liquid state and at the same time prevent blood loss and thrombosis. Defects in the blood coagulation system (hemostasis) can be genetic, that is, inherited, or acquired. Impaired hemostasis can predispose both to bleeding and hemorrhage (for example, the well-known hemophilia) and to increased blood clotting (thrombophilia). The latter are observed much more often. Obstetrician-gynecologists often encounter such disorders, since many complications of pregnancy and childbirth are accompanied by bleeding and thrombosis. In recent years, it has been established that blood clotting disorders, both genetically determined and acquired in many autoimmune diseases, can cause intrauterine fetal death, miscarriage, infertility, and serious pregnancy complications (preeclampsia, premature placental abruption, anemia, etc.). Studying the blood coagulation system in such cases allows us to answer many unclear questions. Long-term chronic infections, stress, trauma, obesity, endocrine and oncological diseases, and long-term use of certain medications lead to acquired hemostasis disorders. Among the bad habits that lead to changes in blood clotting is smoking. It is not without reason that smoking is considered one of the leading causes in the risk group for stroke and heart attack. Smoking leads to increased blood clotting and predisposes to thrombosis, and this, in turn, serves as a leading mechanism for stroke and heart attack. The situation becomes even more complicated if the smoker has genetic defects in the coagulation system. With age, the activity of the coagulation component of hemostasis also increases. Therefore, age is also a risk factor for strokes and heart attacks. The most common causes of blood clotting disorders include: - antiphospholipid syndrome - a pathology in which the formation of antibodies to the phospholipids of the body's own occurs. Manifestations of antiphospholipid syndrome include not only obstetric complications (early miscarriages, gestosis, placental insufficiency, etc.), but also various cardiovascular, neurological, and skin manifestations. - hereditary disorders of hemostasis as a result of disturbances in the structure of certain genes (Leiden mutation, hyperhomocysteinemia, deficiencies of natural anti-clotting proteins - proteins C, S and antithrombin III, etc. Normally, pregnancy is accompanied by an increase in blood clotting, especially in the last stages. This is a device that prevents pathological blood loss during childbirth. In the presence of hemostasis disorders that predispose to thrombosis, pregnancy without appropriate correction of these disorders is often accompanied by serious complications: gestosis, premature placental abruption, threat of miscarriage, miscarriages at different stages and premature birth, as well as increasing the risk of death from stroke and heart attack due to the formation of blood clots.Disorders of hemostasis may not show themselves at all before pregnancy, but manifest themselves during pregnancy, during any surgical interventions or when using hormonal contraception. Pregnancy may not occur at all, since such disorders lead to the loss of the embryo in the early stages (especially with antiphospholipid syndrome) due to the inability of the fertilized egg to implant into the uterine mucosa. This is called preembryonic fetal loss. Clinically, this is manifested by the next menstruation, and the woman remains infertile with a diagnosis of “unclear form of infertility.” Previously, it was believed that thrombosis was unpreventable. Now, with the advent of modern diagnostics and highly effective drugs, it is possible to prevent them. A study of the blood coagulation system makes it possible to predict in advance the risk of pregnancy complications and take measures to prevent them. Hemostasis testing is recommended for all women planning pregnancy, especially those who suffer from obesity, hypertension, varicose veins, and infertility; who have had a history of miscarriage and premature birth, stillbirth, complications during previous pregnancies and births, unsuccessful attempts at in vitro fertilization, whose mothers and grandmothers had pregnancy complications. Some important diagnostic methods (especially the determination of genetic forms of thrombophilia) remain very complex and expensive, and therefore not always available. Nevertheless, a great achievement is that knowing this or that pathology of hemostasis even before pregnancy or at its earliest stages, you can carry out preventive treatment and achieve pregnancy, prolong pregnancy until the optimal due date in women with miscarriage, and even save your life and Your future child. Today, a whole group of medications is used at the stage of pregnancy planning. These include drugs that prevent platelet aggregation, anticoagulants, polyunsaturated fatty acids, antioxidants, folic acid and vitamin-mineral complexes. This or that therapy is prescribed depending on the form and degree of hemostatic impairment individually. Treatment continues throughout pregnancy. In this case, the probability of a successful pregnancy outcome is high and, with proper and timely treatment, reaches 95%.

Rules for conducting hCG analysis

Where to take an hCG test, everyone decides for themselves. But it is important to prepare for it correctly in any case. To perform this, blood is taken from a vein. Among the general recommendations, we will give some, if you have not received them from your doctor:

• It is recommended to donate blood strictly on an empty stomach in the morning;
• when taking the hCG test at another time, it is important to abstain from eating for 5-6 hours;
• Tell your healthcare provider if you are taking any hormonal medications.

To conduct a laboratory test for early pregnancy, blood is taken no earlier than 4-5 days after a missed period. To clarify the results, the study is repeated after 2-3 days.

At the IVF Center clinic, it is also possible to carry out an urgent test for beta-hCG. To screen out possible pathologies in the fetus, the study is carried out at 14-18 weeks of pregnancy in parallel with ultrasound diagnostics.

The hormone level in a pregnant woman is an informative indicator of the normal development of the fetus, facilitating the diagnosis of various pathologies at the earliest stages.

PAPP-A – protein

PAPP-A is needed for the growth and development of the placenta, so this level increases as pregnancy progresses. If the fetus has a chromosomal abnormality, then this enzyme often decreases between 8 and 14 weeks of pregnancy - precisely at the time of the first screening.

The lower the PAPP-A level, the more severe the child’s defect may be - from trisomy 21, 18 or 13 (Down, Edwards and Patau syndrome, respectively), to Cornelia de Lange syndrome - a severe genetic pathology with multiple developmental defects. The nuance is that after 14 weeks, even with serious disorders and anomalies in the fetus, the level of PAPP-A is in accordance with the norm in the specified period. Therefore, this substance must be analyzed within a certain period of time.

WHY DOES AN ANDROLOGIST NEED THIS ANALYSIS?

1. Identifying the causes of male infertility;
2. Forecast of the effectiveness of conservative therapy (dietary supplements, multivitamins, amino acids, hormonal stimulation, etc.);
3. Choosing a method and predicting the effectiveness of the chosen method of infertility treatment (natural conception or IVF/ICSI).

! If a genetic factor of infertility is identified, the management tactics of a married couple may radically change; in some cases, it is necessary to carry out pre-implantation diagnostics of the fetus in order to exclude the transmission of a genetic disease to offspring.

MICRODELETIONS OF AZF – REGIONS (A, B, C) Y-CHROMOSOME, WHAT IS THIS?

This study allows us to establish the genetic causes of reproductive dysfunction in men and evaluate the effectiveness of treatment procedures. AZF - regions of the male Y chromosome include a large number of genes responsible for sperm production. Deletions, i.e. loss of these genes leads to impaired spermatogenesis. The most studied are AZFа, AZFb and AZFс. These mutations are found in 11% of men with azoospermia and in 8% of men with severe oligospermia. The analysis period is usually at least 19 working days. Material for research: whole blood.

Genetic determination of paternity/maternity (2 participants: child and intended parent)

A DNA paternity/maternity test allows you to determine whether a man/woman is the biological father/mother of a particular child or not. The molecular genetic research method is based on the identification of alleles of a number of polymorphic loci that are uniquely inherited by a child from biological parents. DNA isolated from biological material obtained from the individuals being examined is subject to research. In every person, the cells of biological material (blood, saliva, bones, skin, muscles, teeth, hair follicles, etc.) contain absolutely the same DNA. It remains constant throughout life, without undergoing changes. Therefore, the results of molecular genetic research do not depend on what kind of biological material is studied in a particular case. Typing of polymorphic STR loci of chromosomal DNA is carried out using polymerase chain reaction using enzymatic amplification of the 25-locus panel VeriFiler™ Express PCR Amplification Kit (ThermoFisher Scientific, USA), guided by guidelines No. 98/253 “Use of individualizing systems based on length polymorphism of amplified fragments (PDAF) of DNA in forensic medical examination of personal identification and establishment of kinship" (approved by the Ministry of Health of the Russian Federation on January 19, 1999) and the instructions of the manufacturer. The identified alleles of the studied loci are designated in accordance with the standard international nomenclature, which allows, if necessary, interlaboratory comparisons of the results obtained. Using a sample from the biological mother (whose relationship is not in dispute) greatly improves the accuracy of the analysis. There are two possible analysis results: (1) “exclusion of paternity/maternity” and (2) “non-exclusion of paternity/maternity.” The probability for “non-exclusion of paternity/maternity” is 99.9999% or higher (100% accuracy for non-exclusion of paternity/maternity is theoretically unattainable). If there are matching alleles for all studied loci in the child and the putative father, a conclusion is made about the possibility of the child receiving hereditary material from the person being examined: “non-exclusion” of paternity/maternity. The probability when excluding paternity/maternity is 100%. A conclusion about the exclusion of paternity/maternity is made if there are no matching alleles in the genotypes of the child and the alleged father/mother, even at individual loci.

* 2 participants: child and intended parent.

Research method

PDF analysis of STR DNA loci.

What is genetic determination of paternity/maternity?

Establishing paternity/maternity means proving by genetic methods that the alleged father of a child is his biological father.

Comparison of genetic STR profiles (STR - Short Tandem Repeats) based on genotyping at 16 loci using the AmpFSTR® Profiler Plus® PCR Amplification Kit and GORDIZ CoDIS-18 on the GE Healthcare Life Sciences MegaBACE 1000 automatic sequencer. Additional confirmatory research is carried out up to 20 loci with insufficient probability obtained. The method meets the requirements established in forensic medicine. Legally evidentiary or anonymous research is possible. Guaranteed probability when confirming kinship: no less than 99.75%.

What material is used for genetic testing?

As a material for analysis, you can use blood and scrapings of the buccal epithelium (mucosal cells on the inside of the cheek). You can also use a hair with a hair follicle or even a dried blood spot, which will allow analysis without exposing the child to medical procedures. DNA is extracted from the collected biological samples and examined using the PCR (polymerase chain reaction) method. Execution time up to 10 days. It is possible to conduct the analysis anonymously.

Testing can be done at any age.

Rules for the inheritance of genetic information

1. The child inherits 2 alleles of each autosomal marker (one from the mother, the other from the father)
2. Mitochondrial DNA is inherited by the child from the mother
3. A male child inherits the paternal haplotype on the Y chromosome

At the moment of conception of a child, the fusion of the mother’s egg and the biological father’s sperm, containing haploid sets of chromosomes (23 chromosomes each), occurs. After fertilization, these two haploid sets of chromosomes form the baby's diploid set of chromosomes (23 pairs of chromosomes). Of these, 22 pairs of autosomes (the same in male and female organisms) and two sex chromosomes (the X chromosome is inherited from the mother, and either the X chromosome or the Y chromosome is inherited from the father). Thus, the child receives half of the genetic material from the mother and the other half from the biological father.

What is genetic testing?

DNA analysis involves the direct study of the genetic material that a child inherits from his biological parents, based on Mendel's theory of heredity.

Each chromosome consists of DNA, which is a unique sequence of nucleotides for each person - the genetic code. The DNA sequence contains many highly polymorphic regions (loci) - short tandem repeats (STR). These are repeats of two or more pairs of immediately adjacent nucleotides. The length of a short tandem repeat is typically between 2 and 10 base pairs (e.g., (CATG)n), and the number of repeats within a locus is highly individual. To establish relationship, a study of the number of STR repeats in a locus is used. The identified variants (alleles) are compared, and thus it can be determined that one allele was inherited by the child from the mother, and the second from the father. If the child's allele does not match either of the father's two alleles, biological paternity is completely excluded. The probability of differences in alleles due to a mutation that has occurred is also taken into account (for STR loci, the probability of its occurrence ranges from 0.1 to 0.4%).

An example of analysis for one STR locus. 1. Coincidence of loci sizes in the child and the putative father. 2. Lack of a match for the studied locus in the child and the putative father.

Modern methods of DNA research make it possible to establish kinship by analyzing STR sequences of nuclear DNA and sex chromosomes, as well as the sequence of nucleotides in mitochondrial DNA (to establish kinship in the female line).



How accurate is a genetic test?

Only those alleles of polymorphic loci that are found in the mother and biological father can be present in the child’s genome. Therefore, if the child and the father have a match of at least one allele in each locus under study, paternity can be confirmed with a probability of 99.75-99.99%. To achieve this accuracy, 16 to 20 different loci are examined. If the answer is “not the biological father,” the test accuracy is 100%.

When three samples are analyzed (mother, child, suspected father), a minimum probability of paternity of 99.9% is guaranteed. In the absence of the mother (only father and child samples are examined), the minimum guaranteed value is slightly lower - 99.75%. That is, an error is possible only in one case out of 10,000. A negative answer is 100% accurate.