Mazza Vincenzo, Latella Silvia, Fenu Valentina, Ferrari Paola, Bonilauri Carlotta, Santucci Sandra, Percesepe Antonio
Department of Obstetrics and Gynaecology, University of Modena, Modena, Italy.
J Obstet Gynaecol Res. 2010 Oct;36(5):1116-20. doi: 10.1111/j.1447-0756.2010.01278.x. Epub 2010 Aug 17.
We report on the case of a patient with mosaic trisomy 22, who was diagnosed prenatally by amniocentesis during the 16(th) week of pregnancy. In the foetus, three trisomic clones were found out of the nine that were analyzed (the other six clones had a 46,XY karyotype). Cytogenetic analysis of cord blood during the 20(th) week of pregnancy showed a normal male karyotype; however, a placental biopsy that was performed at the same time showed 100% and 95% trisomic cells in the chromosomal analysis of direct and long-term cultures, respectively. A follow-up ultrasonographic examination excluded major congenital malformations and the abdominal and cranial circumferences were normal until the 24(th) week of pregnancy. At this point, a deflection of the growth curve occurred and the values were persistently below the 3(rd) centile until birth. After birth, karyotypic and fluorescent in situ hybridisation analyses performed on the fibroblasts of the neonate showed that 3-4% of the cell lines were trisomic, and studies using microsatellite markers showed normal allelic segregation, which excluded uniparental disomy. The period of postnatal follow-up was characterised by a significant growth deficit (height and head circumference were less than the 3(rd) centile) and by mental retardation. The present case is compatible with other earlier reports that showed that the levels of trisomy 22 are tissue-specific and are of little help in establishing the prognosis of the chromosomal abnormality.
我们报告了一例22号染色体嵌合三体患者的病例，该患者在妊娠16周时通过羊膜穿刺术进行产前诊断。在胎儿中，分析的9个克隆中有3个三体克隆（其他6个克隆具有46,XY核型）。妊娠20周时脐带血细胞遗传学分析显示核型正常为男性；然而，同时进行的胎盘活检在直接培养和长期培养的染色体分析中分别显示100%和95%的三体细胞。随访超声检查排除了主要先天性畸形，直到妊娠24周时腹围和头围均正常。此时，生长曲线出现偏差，直至出生时各项数值持续低于第3百分位数。出生后，对新生儿成纤维细胞进行的核型分析和荧光原位杂交分析显示3 - 4%的细胞系为三体，使用微卫星标记的研究显示等位基因分离正常，排除了单亲二体。产后随访期间的特征为明显的生长发育迟缓（身高和头围均小于第3百分位数）以及智力发育迟缓。本病例与其他早期报告一致，这些报告表明22号染色体三体水平具有组织特异性，对确定染色体异常的预后帮助不大。
