Crowe C A, Schwartz S, Black C J, Jaswaney V
Department of Pediatrics, Metrohealth Medical Center, Cleveland, Ohio 44109-1998, USA.
Am J Med Genet. 1997 Sep 5;71(4):406-13.
In a case of mosaic trisomy 22 the trisomic cells were detected primarily in fibroblasts. Results of initial lymphocyte chromosome analysis were normal. However, mosaicism was suspected because the patient had hypomelanosis of Ito, hemiatrophy, failure to thrive, and mental retardation. Mosaicism was confirmed in cultured fibroblasts. Repeat cytogenetic analysis of peripheral blood demonstrated a low level of trisomic metaphase cells, which was confirmed by interphase fluorescent in situ hybridization (FISH) analysis. Molecular studies supported maternal disomy in the child's disomic cells. The phenotype of this condition overlaps that of non-mosaic trisomy 22 chromosome mosaicism in general and to some extent the Ullrich-Turner syndrome phenotype. Improved cytogenetic and molecular techniques now allow better delineation of aneuploidy syndromes. Molecular and FISH studies added information about this case (mosaicism and uniparental disomy) not appreciated by routine cytogenetic analysis of lymphocytes. The detection of low-level mosaicism and/or uniparental disomy in such cases may change the clinical classification and our understanding of pathogenesis and recurrence risk of these disorders.
在一例22号染色体嵌合三体病例中，三体细胞主要在成纤维细胞中被检测到。初始淋巴细胞染色体分析结果正常。然而，由于患者存在伊藤色素减退症、偏侧萎缩、生长发育迟缓及智力障碍，怀疑存在嵌合体现象。在培养的成纤维细胞中证实了嵌合体的存在。对外周血进行重复细胞遗传学分析显示三体中期细胞水平较低，这通过间期荧光原位杂交（FISH）分析得以证实。分子研究支持患儿二体细胞中存在母源二体。这种病症的表型总体上与非嵌合型22号染色体三体嵌合体的表型重叠，在一定程度上也与乌尔里希 - 特纳综合征表型重叠。如今，改进后的细胞遗传学和分子技术能够更好地界定非整倍体综合征。分子研究和FISH研究提供了关于该病例（嵌合体和单亲二体）的信息，而这些信息通过淋巴细胞的常规细胞遗传学分析无法得知。在此类病例中检测到低水平嵌合体和/或单亲二体可能会改变这些疾病的临床分类以及我们对其发病机制和复发风险的理解。
