Tsukamoto H, Inui K, Taniike M, Kamiyama K, Hori M, Sumi K, Okada S
Department of Pediatrics, Osaka University School of Medicine, Japan.
Clin Genet. 1993 Mar;43(3):139-42. doi: 10.1111/j.1399-0004.1993.tb04438.x.
We present male monozygotic twins who showed quite different clinical features. Blood chromosome analysis revealed 46,XY/46,XY,del(7) (q32-->qter) mosaicism in both twins. However, cultured skin fibroblasts from the twins showed different karyotypes. Twin 1, with a normal phenotype, had normal chromosomes and was 46,XY. Twin 2, on the other hand, had the characteristic manifestations of 7q- syndrome and chromosomes of 46,XY,del(7) (q32-->qter). DNA fingerprint analysis of their peripheral blood samples revealed the same pattern. However, DNA fingerprint patterns of cultured skin fibroblasts and buccal mucosal cells were different when a 7q terminal marker, probe g3, was used. These identical twins with discordant phenotypes can be explained by the occurrence of twinning and simultaneous erroneous mitosis. In addition, there might be a vascular communication which probably resulted in blood exchange and chromosomal mosaicism of the lymphocytes of the monozygotic twins.
我们报告了一对男性同卵双胞胎，他们表现出截然不同的临床特征。血液染色体分析显示，双胞胎两人均存在46,XY/46,XY,del(7)(q32→qter)嵌合体。然而，双胞胎的培养皮肤成纤维细胞显示出不同的核型。双胞胎1表型正常，染色体正常，核型为46,XY。另一方面，双胞胎2具有7q-综合征的特征性表现，染色体为46,XY,del(7)(q32→qter)。对他们外周血样本的DNA指纹分析显示出相同的模式。然而，当使用7q末端标记探针g3时，培养的皮肤成纤维细胞和颊黏膜细胞的DNA指纹模式不同。这对具有不一致表型的同卵双胞胎可以通过双胎发生和同时发生的错误有丝分裂来解释。此外，可能存在血管交通，这可能导致了单卵双胞胎淋巴细胞的血液交换和染色体嵌合体。
