摘要
本文对三例X染色体结构异常46,X,dup(X)(p21);46,X,del(X)(p11);46,X,i(Xq)患者及其父母,用X染色体短臂或长臂上的限制性片段长度多态性(RFLPs)作为遗传标记,研究了异常X染色体的起源和形成机理。结果表明,dup(X)(p21)和del(X)(p11)起源于父方,而i(Xq)起源于母方。dup(X)(p21)是由X染色体姊妹染色单体不均等的互换所引起的,del(X)(p11)是由于X染色体断裂后丢失所致,i(Xq)的发生是由于卵母细胞X染色体着丝粒错分裂。
In this study, we analysed the parental origin and mechanism of X chromosome abnorma-lites in 3 cases by using RFLPs on short or long arm of X chromosome as genetic markers. Their karyotypes were 46,X,dup(X)(p21); 46,X,del(X)(p11); 46,X,i(Xq). The results demonstrated that the dup(X)(p21) and the del(X)(pll) were of paternal origin and i(Xq) was of maternal origin. The dup(X)(p21) arose from an unequal sister chromatid exchange. The del(X) (p11) occurred through X chromosome breakage and deletion machanism. The i(Xq) resulted from X chromosome centromere misdivision in oocyte.
