Summary of this article

Vanishing twins is a phenomenon in which one fetus disappears during pregnancy. The effects on the mother and the remaining fetus, causes, and precautions are explained in detail.

Vanishing Twin is a phenomenon in which one of the fetuses that starts developing as a twin in the early stages of pregnancy disappears during development. The impact of this phenomenon on prenatal paternity testing should be considered, in particular with regard to

1. Mixing fetal DNA samples

When vanishing twins occur, the lost fetal DNA may remain in the mother’s blood or amniotic fluid. In this case, the DNA of the lost fetus may be mixed with the fetal DNA sample taken before birth. This may complicate the DNA test results.

2. interpretation of expert testimony

Effects of mixed DNA: if the DNA of the vanishing twin is mixed with the DNA of the remaining fetus, the DNA profile detected may be different from normal. This can lead to ambiguous test results and make it difficult to accurately determine the parent-child relationship.
Occurrence of pseudo diversity: normally, the DNA of a single fetus has genetic material from two parents, but if the DNA profile contains several different genetic information due to the vanishing twin, this can lead to errors in determining parent-child relationships.

3. Measures and considerations

High-precision testing methods: the effects of the vanishing twin need to be taken into account in the analysis. High-precision DNA analysis techniques make it easier to distinguish between fetal DNA and vanishing twin DNA.
Need for additional testing: if there is a possibility of a vanishing twin when performing a prenatal paternity test, consider additional testing or retesting at a later date (postnatal DNA testing) to ensure confidence in the results of the test</a5> It is important to.

Summary

Vanishing twins can affect prenatal paternity testing. In particular, the presence of DNA from a vanished twin in a fetal DNA sample can lead to ambiguous results of the analysis. For this reason, high-precision analysis and additional testing is recommended in cases of possible vanishing twins. This is a case that requires expert judgement and careful inspection methods.

医師監修監修日：2024年8月28日

岡博史（おかひろし）

医師・医学博士／ヒロクリニック統括院長

YouTubeチャンネルなどを通じて、遺伝子やNIPT（新型出生前診断）についてわかりやすく発信しています。

略歴

1996年慶應義塾大学医学部卒業
2004年慶應義塾大学医学博士号取得
2005年慶應義塾大学皮膚科学教室助手
2008年ヒロ皮フ形成クリニック開業
2009年医療法人社団福美会理事長
2015年医療法人社団福美会理事

資格・所属

CAPラボディレクター
日本皮膚科学会皮膚科専門医
日本医師会産業医
東京衛生検査所指導監督医

発信・関連リンク

この記事は、ヒロクリニックNIPPTの編集・監修体制にもとづき、資格を持つ医師が内容を確認しています。

医師監修監修日：2024年8月28日

堤修一（つつみしゅういち）

医師・医学博士／ヒロクリニック博多駅前院院長

略歴

1993年東京大学医学部医学科卒業
2016〜2019年東京大学先端科学技術研究センター准教授

発信・関連リンク

プロフィール詳細

この記事は、ヒロクリニックNIPPTの編集・監修体制にもとづき、資格を持つ医師が内容を確認しています。

参考文献

Landy HJ, Keith LG. The vanishing twin: a review. Hum Reprod Update. 1998;4(2):177-183.
Curnow KJ, Wilkins-Haug L, Ryan A, Kirkizlar E, Schmid M, Sigurjonsson S, Demko Z. Detection of triploid, vanishing twin, and molar pregnancies by single-nucleotide polymorphism-based noninvasive prenatal testing. Am J Obstet Gynecol. 2015;212(1):79.e1-79.e9.