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Abstract：
Turner syndrome (TS) is caused by a complete or partial absence of an X or Y chromosome, including chromosomal mosaicism, affecting 1 in 2500 female live births. Sister chromatid exchange (SCE) is used as a sensitive indicator of spontaneous chromosome instability. Cells from mosaic patients constitute useful material for SCE evaluations as they grow under the influence of the same genetic background and endogenous and exogenous factors. We evaluated the proliferation dynamics and SCE frequencies of 45,X and 46,XN cells of 17 mosaic TS patients. In two participants, the 45,X cells exhibited a proliferative disadvantage in relation to 46,XN cells after 72 h of cultivation. The analysis of the mean proliferation index (PI) showed a trend for a significant difference between the 45,X and 46,X+der(X)/der(Y) cell lineages; however, there were no intra-individual differences. On the other hand, mean SCE frequencies showed that 46,X+der(X) had the highest mean value and 46,XX the lowest, with 45,X occupying an intermediate position among the lineages found in at least three participants; moreover, there were intra-individual differences in five patients. Although 46,X+der(X)/der(Y) cell lineages, found in more than 70% of participants, were the most unstable, they had a slightly higher mean PI than the 45,X cell lineages in younger (≤17 years) mosaic TS participants. This suggests that cells with a karyotype distinct from 45,X may increase with time in mosaic TS children and adolescents.
摘要：
特纳综合征（TS）是由X或Y染色体完全或部分缺失引起的，包括染色体镶嵌，影响2500名女性活产婴儿中的1名。姐妹染色单体交换（SCE）被用作自发染色体不稳定性的敏感指标。来自镶嵌患者的细胞在相同的遗传背景以及内源性和外源性因素的影响下生长时，构成了SCE评估的有用材料。我们评估了17例马赛克TS患者的45，X和46，XN细胞的增殖动力学和SCE频率。在两名参与者中，培养72小时后，45，X细胞相对于46，XN细胞表现出增殖劣势。平均增殖指数（PI）的分析显示，45，X和46，Xder（X）/der（Y）细胞谱系之间存在显着差异的趋势；但是，没有个体差异。另一方面,平均SCE频率显示，46，X+der(X)的平均值最高，46，XX的平均值最低，45，X在至少三个参与者的谱系中占据中间位置；此外，5例患者存在个体差异.虽然46，X+der(X)/der(Y)细胞谱系，在超过70％的参与者中发现，是最不稳定的，在年轻(≤17岁)马赛克TS参与者中,他们的平均PI略高于45,X细胞谱系.这表明，在马赛克TS儿童和青少年中，核型不同于45，X的细胞可能会随着时间的推移而增加。
