Supernumerary small marker chromosome (SMC) and uniparental disomy 22 in a child with confined placental mosaicism of trisomy 22: Trisomy rescue due to marker chromosome formation
Supernumerary small marker chromosome (SMC) and uniparental disomy 22 in a child with confined placental mosaicism of trisomy 22: Trisomy rescue due to marker chromosome formation
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DOI：
10.1159/000074163
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发表时间：
2003-01-01
影响因子：
1.7
通讯作者：
Burfeind, P
中科院分区：
文献类型：
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作者：
Bartels, I;Schlueter, G;Burfeind, P
三体挽救是多馀小标记染色体(SMC)和单亲二体(UPD)形成的多种机制之一。在本报告中，由于母亲年龄的原因，在产前诊断中诊断出一条来自14号或22号染色体的小的从头标记染色体。出生时随访发现嵌合体为47，XX，+MAR/46，XX。用FISH检测，该标记对探针D14/22Z1呈阳性，而对探针MIDI 54和D22Z4呈阴性。利用三个信息标记，两条染色体都被证明是从母亲(UPDmat)那里遗传来的。这一结果与母体减数分裂I的不分离一致。女孩现在18个月大，表型正常。超声检查排除心脏和腹部畸形。运动和智力发育是根据或早于发育里程碑(10个月自由行走，12个月第一次说话)。这一案例证实了母体UPD 22很可能与临床异常无关。根据FISH结果，胎盘中的UPD 22和47，XX，+22，SMC来自22号染色体的α卫星序列。这一案例首次证明，早期合子后将染色体减少为小的标记染色体是挽救三体受孕的真正存在的机制。版权所有(C)2003 S.Karger AG，巴塞尔。
Trisomy rescue is one of various proposed mechanisms in formation of supernumerary small marker chromosomes (SMC) and uniparental disomy (UPD). In the present report a small de novo marker chromosome derived from chromosome 14 or 22 was diagnosed at prenatal diagnosis due to maternal age. Follow up investigations at birth revealed mosaicism 47,XX,+mar/46,XX. Using FISH, the marker was positive for the probe D14/22Z1, but negative for the probes midi 54 and D22Z4. Using three informative markers both chromosomes 22 were shown to be inherited from the mother (UPDmat). The results are consistent with nondisjunction at maternal meiosis I. The girl is 18 months old now and phenotypically normal. Cardiac and abdominal malformations were excluded by sonographic examinations. Motor and mental development is according to or ahead of developmental milestones (free walking with 10 months, first words at 12 months). The case confirms that maternal UPD 22 most likely is not associated with clinical abnormalities. According to FISH results, UPD 22, and 47,XX,+22 in the placenta, we conclude that the SMC was derived from alpha satellite sequences of chromosome 22. This case for the first time gives evidence that early postzygotic reduction of a chromosome to a small marker chromosome is a real existing mechanism to rescue a conceptus with trisomy. Copyright (C) 2003 S. Karger AG, Basel.