Wang J-C, Hajianpour A, Habibian R
Genzyme Genetics, Monrovia, CA 91016, USA.
Cytogenet Genome Res. 2009;125(4):329-33. doi: 10.1159/000235939. Epub 2009 Oct 27.
In the process of selecting fluorescence in situ hybridization probes to be used for preimplantation genetic diagnosis in couples with balanced reciprocal translocations, we found 2 individuals with unexpected breaks in the centromeric alpha-satellite DNA. Subsequently, centromere breaks were specifically sought in reciprocal translocations in which 1 or both breakpoints appeared cytogenetically near the centromere. In a total of 11 individuals studied, we found 8 centromere breaks in 6 individuals; in 2 individuals, the alpha-satellite DNA of both chromosomes involved in the translocation split into 2 arrays. These findings suggest that breaks in alpha-satellite DNA are not rare events. Together with those previously reported in the literature, alpha-satellite DNA breaks of at least chromosomes X, 1, 4, 5, 10, 11, 16, 17, 18, and 19 have now been documented. The breaks are familial in 2 of the 6 cases in our study, indicating the derivative chromosomes are both mitotically and meiotically stable. These derivative chromosomes that are either cytogenetically dicentric or molecular cytogenetically dicentric, or have altered amounts of alpha-satellite DNA may prove to be valuable in studying centromere dynamics and biology.
在为携带平衡易位的夫妇选择用于植入前基因诊断的荧光原位杂交探针的过程中，我们发现2例个体的着丝粒α卫星DNA出现意外断裂。随后，在1个或2个断点在细胞遗传学上靠近着丝粒的相互易位中专门寻找着丝粒断裂。在总共研究的11例个体中，我们在6例个体中发现了8处着丝粒断裂；在2例个体中，易位涉及的两条染色体的α卫星DNA均分裂成2个阵列。这些发现表明，α卫星DNA断裂并非罕见事件。连同文献中先前报道的那些，现在已经记录了至少X、1、4、5、10、11、16、17、18和19号染色体的α卫星DNA断裂。在我们研究的6例病例中有2例的断裂是家族性的，这表明衍生染色体在有丝分裂和减数分裂中都是稳定的。这些细胞遗传学上双着丝粒或分子细胞遗传学上双着丝粒、或α卫星DNA含量改变的衍生染色体，可能在研究着丝粒动力学和生物学方面具有重要价值。
