Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, PA, USA.
Am J Med Genet A. 2011 Oct;155A(10):2489-95. doi: 10.1002/ajmg.a.34172.
Mosaic trisomy 17 is rare with only 28 cases reported and the clinical presentation is highly variable. The diagnosis is most commonly made by prenatal karyotype and in most cases is followed by a normal postnatal karyotype on blood lymphocytes.We present two cases of mosaic trisomy 17 diagnosed prenatally,with follow up in multiple tissues at birth. In the first case,trisomy 17 was identified in all amniocytes, and at birth standard results of chromosome analysis in peripheral blood were normal,but mosaic trisomy 17 was identified (50–75%) in skin fibroblasts by genome-wide SNP array analysis. This patient presented with congenital heart disease, asymmetry, intestinal malrotation, and other anomalies and died on day 9 of life. In the second patient amniocentesis after ultrasound finding of tetralogy of Fallot showed mosaic trisomy 17. Postnatally, results of a SNP array were normal in blood, buccal mucosa, and skin. It is possible that the cardiac defect is related to trisomy 17 in key tissues during heart development, although at birth the aneuploidy could not be identified in tissues that are routinely analyzed for diagnosis. These cases add to our understanding of mosaic trisomy 17, highlighting the failure to diagnose this aneuploidy in peripheral blood.
嵌合型 17 三体非常罕见，仅有 28 例报道，临床表现高度可变。诊断通常通过产前核型进行，大多数情况下，在血液淋巴细胞中会出现正常的产后核型。我们报告了两例产前诊断为嵌合型 17 三体的病例，并在出生时对多种组织进行了随访。在第一个病例中，所有羊水细胞均存在 17 三体，出生时外周血染色体分析的标准结果正常，但通过全基因组 SNP 微阵列分析发现皮肤成纤维细胞存在嵌合型 17 三体（50-75%）。该患者患有先天性心脏病、不对称、肠旋转不良和其他畸形，并于出生后第 9 天死亡。在第二个病例中，在超声发现法洛四联症后进行羊膜穿刺术，显示存在嵌合型 17 三体。出生后，血液、口腔颊黏膜和皮肤的 SNP 微阵列结果正常。心脏缺陷可能与心脏发育过程中关键组织的 17 三体有关，尽管在出生时，不能在常规用于诊断的组织中识别出非整倍体。这些病例增加了我们对嵌合型 17 三体的认识，突出了在外周血中未能诊断出这种非整倍体的情况。
