Technical background and mechanics of DNA prenatal parentage testing.

1. what is DNA prenatal paternity testing?

DNA prenatal paternity tests use fetal DNA to confirm the parent-child relationship with the father. It is mainly carried out in the following situations

• Legal reasons: where the parent-child relationship is legally necessary (e.g. in relation to inheritance rights or parental rights)
• Family circumstances: where confirmation of the parent-child relationship within the family is required
• Genetic risk assessment: to assess the risk of genetic diseases and disorders

Prenatal paternity testing provides an early means of providing important information for families, as results can be obtained before the child is born.

2. Technical background and mechanisms

2.1 Genetics basics

DNA (deoxyribonucleic acid) is present in all living organisms and holds genetic information. Human DNA is stored in 46 chromosomes, which contain genes inherited from parents. Confirmation of the parent-child relationship is done by comparing these genes. Specifically, as half of the genes are inherited from the father and half from the mother, the relationship is confirmed by finding genetic markers that match between the parent and child.

2.2 Methods of obtaining fetal DNA

There are three main methods of obtaining fetal DNA

1. Chorionic villus sampling (CVS):
   • Time of implementation: between 6 and 12 weeks of pregnancy .
   • Methods: chorionic villi, part of the placenta, are collected and analyzed for their DNA.
   • Risk: There is a slight risk of miscarriage, but the results are available relatively early.
2. Amniotic fluid testing:
   • Time of implementation: between 15 and 20 weeks’ gestation.
   • Method: amniotic fluid is collected and analyzed for fetal DNA in it.
   • Risk: There is a risk of miscarriage, but relatively detailed genetic information can be obtained.
3. Non-invasive prenatal genetic testing (NIPT):
   • Time of implementation: from 6 weeks of pregnancy onwards.
   • Methods: analysis of fetal DNA fragments from maternal blood.
   • Risk: Non-invasive, safe and without risk of miscarriage. However, a positive result requires additional definitive diagnosis.

2.3 Data analysis and identification of parent-child relationships

The acquired DNA samples are analyzed by the following process:

1. DNA extraction and amplification:
   • DNA extraction: extracts DNA from the sample.
   • Amplification: amplification techniques (e.g. polymerase chain reaction (PCR)) are used to amplify the portion required for testing.
2. Gene comparison:
   • Comparison of genetic markers: compares the DNA of the mother, father and fetus, looking for genetic markers that match the parent-child relationship.
   • Checking for concordance: the concordance rate of genetic markers determines whether a parent-offspring relationship can be confirmed.
3. Interpretation of results:
   • Reporting results: reports whether or not a parent-child relationship exists. Highly accurate test results are often obtained, but interpretation of the results requires specialist knowledge.

3. Accuracy and Limitations

3.1 Accuracy

DNA prenatal parentage testing is highly accurate but does not provide complete certainty. In particular, non-invasive prenatal genetic testing (NIPT) is used not only to confirm parent-child relationships but also to assess the risk of genetic disorders. Although the test is highly accurate, a positive result may not always be definitive. Therefore, in the event of a positive result, additional definitive diagnosis is recommended.

3.2 Limitations

• Risk of false positives: especially with NIPT, positive results may not always be definitive. Due to the risk of false positives and false positives, it is important to use other tests in conjunction.
• Cost and access: some prenatal paternity tests are expensive and not available to all. In addition, there are some areas where testing is difficult to carry out.
• Interpreting test results: even highly accurate tests require specialist knowledge to interpret the results. It is important to evaluate the results in consultation with your healthcare provider or specialist.

4. Ethical and Legal aspects

4.1 Ethical aspects

Prenatal paternity testing involves a number of ethical issues. The following are the main ethical aspects

• Purpose and use of the test: clear guidelines are needed on the purpose for which the test is performed and how the results will be used. It is important to consider the impact of the results on the family and society.
• Privacy and consent: personal privacy must be respected and adequate informed consent must be given before any examination is carried out.
• Handling of results: careful consideration must be given to how test results are handled and published. It is important to consider the psychological impact of the results on families and individuals.

4.2 Side of the Law

Laws and regulations on prenatal paternity testing vary from country to country. The following are general legal aspects

• Legal proceedings: legal proceedings regarding verification of parent-child relationship may be required. It is recommended to consult a legal expert as the results of the test may affect legal proceedings.
• Use of test results: there are rules and restrictions on the use of test results. For example, there are laws on how results are recorded and stored.
• Ethical codes and guidelines: medical and laboratory establishments may have set ethical codes and guidelines for prenatal paternity testing. It is important to follow these codes.

5. Future perspectives.

5.1 Evolution of technology

The technology for prenatal parentage testing is evolving rapidly. Further improvements in accuracy and safety are expected in the future. In particular, the evolution of non-invasive testing methods will make testing more accessible and safe for more people.

5.2 Ethical considerations

As technology evolves, ethical considerations are also important. Guidelines on the purpose of testing and the use of results must be in place and the rights of individuals and families must be respected.

5.3 Legal development

The development of legislation and regulations on prenatal paternity testing will increase the transparency of testing. It is hoped that clear regulations on legal procedures and the use of results will be put in place.

6. Summary

DNA prenatal paternity testing has become a powerful tool for confirming parent-child relationships during pregnancy, thanks to advances in technology. Although more accurate and safer testing methods are available, careful consideration must be given to the purpose of the test and the handling of the results. Ethical and legal aspects must also be fully understood and addressed. As technology evolves in the future, it is hoped that an environment will be created in which more people can use the technology with peace of mind.

Hiro Clinic’s DNA Prenatal Paternity Testing

Hiro Clinic’s DNA Prenatal Paternity Testing (NIPPT) is available at the industry’s lowest price at Hiro Clinic’s directly managed locations nationwide. Testing can be done from the 6th week of pregnancy onward, and the process is completed in a single visit, minimizing inconvenience. If a retest is necessary, it will be conducted free of charge, so you can rest assured. Additionally, tests are conducted at the Tokyo Sanitary Laboratory, which has over 50,000 cases of prenatal testing experience, ensuring reliable results. However, both partners are required to visit the clinic to ensure the most accurate test results. For more information, please check here and make your reservation or inquiry.

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Supervisor of the article

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Dr. Hiroshi Oka

Director of CAP Laboratory

Graduated from Keio University, Faculty of Medicine

Doctor of Medicine

Medical Doctor