日本未熟児新生児学会雑誌　第22巻　第1号　57～64頁（2010年）

日本未熟児新生児学会雑誌　22(1)：57-64；2010　

受付日：平成21．02．17

受理日：平成21．06．29

一過性骨髄異常増殖症（TAM）様の好酸球増多症を合併した21トリソミー（ダウン症候群）の2例

Two Cases of Trisomy 21 Complicated with Hypereosinophilia Like TAM

＊1大阪府立母子保健総合医療センター　新生児科，＊2同　遺伝診療科，＊3国立国際医療センター　小児科，＊4ベルランド総合病院　新生児科，＊5いいたに小児科

＊1 Department of Neonatology, Osaka Medical Center and Research Institute for Maternal and Child Health，＊2 Department of Medical Genetics, Osaka Medical Center and Research Institute for Maternal and Child Health，＊3 Department of Pediatrics, International Medical Center of Japan，＊4 Department of Neonatology, Bellland general hospital，＊5 Iitani pediatric hospital

細川真一＊1＊3・和田芳郎＊1＊4・飯谷秀美＊1＊5・北島博之＊1・岡本伸彦＊2

Shinichi HOSOKAWA＊1＊3，Yoshirou WADA＊1＊4，Hidemi IITANI＊1＊5， Hiroyuki KITAJIMA＊1，Nobuhiko OKAMOTO＊2

Key Words：trisomy 21，Down syndrome，TAM，GATA1，hypereosinophilic syndrome

　今回，好酸球増多症合併の21トリソミー症例を2例経験した。症例1は新生児女児で，出生時の外観からは21トリソミーと判断できず，好酸球増多症精査目的での骨髄細胞染色体検査でモザイク型21トリソミーと診断した。ステロイド治療で好酸球増多症は改善し，現在3歳で発達良好である。症例2は新生児男児で出生時の外観から21トリソミーが疑われ，末梢血リンパ球の染色体検査で診断した。一過性好酸球増多を認めたが自然軽快した。11歳時に急性リンパ性白血病を発症し，12歳の現在も化学療法中である。一過性骨髄異常増殖症（transient abnormal myelopoiesis，以下TAM）については，好酸球分化にも寄与する赤血球・巨核球系転写因子GATA1遺伝子の変異が知られている。今回の症例のように，21トリソミーではTAM様の好酸球増多症を発症する可能性も推測される。現時点では，好酸球増多症の発症機序や経過も未知の部分が多く，TAMと同様のフォローが必要である。

　We report two cases of trisomy 21 complicated with hypereosinophilia. As for first case, a newborn female baby was not diagnosed trisomy 21 at first because of her normal appearance at birth. But she was finally diagnosed mosaic trisomy 21 by the chromosome inspection of the bone marrow cell in the purpose of distinct examination for hypereosinophilia. She was treated with steroid therapy and her hypereosinophilia was improved gradually. Now she is 3 years old and her mental development and body growth are normal. As for second case, a newborn male baby was suspected trisomy 21 because of his characteristic appearance at birth, and he was diagnosed by the chromosome inspection of the peripheral blood lymphocyte. Though transient hypereosinophilia was recognized after birth, the condition had improved naturally. He became acute lymphatic leukemia in 11 years old, and he is 12 years old and is receiving the chemotherapy at present. It is known that TAM is related to the modification of transcription factor GATA1 gene which contributes to eosinophilic differentiation. In such as two cases, we thought the possibility that trisomy 21 may complicate with hypereosinophilia like TAM. There are many unknown information in the etiology and progress of hypereosinophilia at present, so it is necessary to follow up similarly the course of patients as TAM.