中国の遺伝子編集ベビー、研究論文が初公開　専門家から「虚偽」と指摘も

【ワシントンＡＦＰ＝時事】昨年中国の研究者がゲノム編集の技術を使ってエイズウイルス（HIV）に耐性がある遺伝子を持つ双子を誕生させた問題で、同研究者が手掛けた研究論文の一部が3日、米業界誌「MITテクノロジーレビュー」で初めて公開された。論文の内容を調べた専門家らは、実施されたゲノム編集が本来の目的を達成しておらず、意図したものではない遺伝子変異を作り出した可能性があると指摘している。（写真は中国・香港で開かれた学会に出席した賀建奎氏）
　ＭＩＴテクノロジーレビューは賀建奎氏の研究が倫理的・科学的な規範を無視していたことを示すのを目的に、論文の抜粋を公開。賀氏は２０１８年末、遺伝子改変を施した双子のルルとナナを誕生させたと発表し、科学界に衝撃を与えた。
　賀氏は研究の成果について、「ＨＩＶの流行を制御」できる医学の飛躍的進歩だと誇示していたが、同氏の研究チームは実際にＨＩＶ耐性を付与する遺伝子変異を再現していないため、双子にＨＩＶの免疫を持たせるという当初の目的を達成したかどうかは不明だった。
　ＣＣＲ５と呼ばれる遺伝子の突然変異によって生まれつきＨＩＶ耐性を持つ人がごく一部いるが、賀氏はゲノム編集技術「クリスパー」を利用し、このＣＣＲ５を編集したと主張していた。
　カリフォルニア大学バークレー校でゲノム編集を専門とするフョードル・ウルノフ氏はＭＩＴテクノロジーレビューに対し、「ＣＣＲ５の変異を再現したという彼らの主張は実際のデータをあからさまにゆがめており、一言で言えば意図的な虚偽である」と指摘。
　賀氏のチームはＣＣＲ５を対象としている一方、必要な「デルタ３２」という変異を再現しておらず、効果のはっきりしない新たなゲノム編集を行ったにすぎない。ウルノフ氏は、「賀氏のチームがＣＣＲ５変異を再現できなかったことは研究結果が示している」と述べている。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2019/12/05-08:42）

The gene edits given to Chinese twins last year meant to immunize them against HIV may have failed in its purpose and created unintended mutations, scientists said Tuesday after the original research was made public for the first time.
Excerpts from the manuscript were released by the MIT Technology Review for the purpose of showing how Chinese biophysicist He Jiankui ignored ethical and scientific norms in creating the twins Lula and Nana, whose birth in late 2018 sent shockwaves through the scientific world.
He made expansive claims of a medical breakthrough that could control the HIV epidemic, but it was not clear whether it had even been successful in its intended purpose -- immunizing the babies against the virus -- because the team did not in fact reproduce the gene mutation that confers this resistance.
A small percentage of people are born with immunity because of a mutation in a gene called CCR5 and it was this gene that He had claimed he had targeted using a powerful editing tool known as CRISPR which has revolutionized the field since bursting on the scene in 2012.
Fyodor Urnov, a genome-editing scientist at the University of California, Berkeley told the MIT Technology Review: The claim they have reproduced the prevalent CCR5 variant is a blatant misrepresentation of the actual data and can only be described by one term: a deliberate falsehood.
The study shows that the research team instead failed to reproduce the prevalent CCR5 variant.
While the team targeted the right gene, they did not replicate the Delta 32 variation required, instead creating novel edits whose effects aren't clear.
Moreover, CRISPR remains an imperfect tool because it can lead to unwanted or off-target edits, making its use in humans hugely controversial.
Here, the researchers claimed they had searched for such effects in the early-stage embryos and found just one -- but this glossed over the fact that it would be impossible to carry out a comprehensive search without inspecting each of the embryo's cells and thus destroying it.
Further ethical concerns included that the parents of the babies might have wanted to take part for the wrong reasons.
The father was HIV positive, which carries a significant social stigma in China and makes it almost impossible to have access to fertility treatment, even though a well-established technique known as sperm washing prevents the infection from being passed on to unborn children.
Their lack of access to any kind of fertility treatment may have motivated them to take part in the experiment despite the huge risks to their children, Jeanne O'Brien, a reproductive endocrinologist at Shady Grove Fertility told the MIT Technology Review.
He attempted to shop his manuscript around to prestigious journals including Nature and JAMA, but it remains unpublished.