臨床婦人科産科71巻9号

2017年09月発行

今月の臨床 着床不全・流産をいかに防ぐか─PGS時代の不妊・不育症診療ストラテジー 胚側因子による流産

受精卵染色体異常の成因と加齢の影響

著者： 中岡義晴¹

所属機関： ¹IVFなんばクリニック

ページ範囲：P.806 - P.814

●形態が良好な胚のなかにも染色体異常が半数以上含まれ，特に女性年齢の上昇によりその異常率は上昇する．異常は主として卵子が原因と考えられる．

●卵子形成と精子形成における減数分裂は大きく異なり，長期間の休止期をもつ卵子は異数性異常が多く，精子は減数分裂後に生じる構造異常が多いのが特徴である．卵子形成には，女性年齢の上昇に伴いコヒーシンなどに異常が生じやすくなることが染色体分離異常の原因となっている．また，受精卵（胚）には受精後の分離異常が原因のモザイクも高頻度に存在する．

●流産の大部分は児の染色体異常が原因であり，流産率を低下させる唯一の方法は胚の染色体を解析する着床前スクリーニングである．

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