一种罕见X染色体改变与X连锁综合征型耳聋的关系

Infrequent X chromosome abnormality and X-linked syndromic deafness

目的 :对一X连锁综合征型耳聋家系进行进一步的遗传学研究 ,以探讨X染色体结构异常与这种综合征型耳聋的内在关系。方法 :用G常规显带、高分辨显带和荧光原位杂交技术对家系成员进行染色体结构和数目分析 ,同时利用X染色体上的遗传标记分析该家系成员的DNA等位片段数。结果 :两例先证者表型正常的母亲及外祖母均存在X(p2 2 pter)重复 ;FISH示先证者及其母亲的X染色体全被涂染 ;DXS710 8等位片段分析示先证者III 3有两个拷贝。结论 :该X连锁综合征型耳聋家系的异常X染色体源于Xp部分重复 。

Objective To make clear the relationship between the X chromosome abnormality and sydromic deafness through genetic analysis of a pedigree with X-linked syndromic deafness.Methods The chromosome number and structure of the family members were analyzed by the standard and high resolution banding with Giemsa, and fluorescent in situ hybridization. The allelic number of the DNA segment in X chromosome was studied with genetic markers.Results The 2 probands, their mothers and grandmother with normal phenotype all had X(p22-pter) duplication. The whole X chromosome of both the proband III-3 and his mother could be stained with X chromosome staining probe. The proband III-3 had 2 copies of DXS7108.Conclusion The abnormal X chromosome occurring in this pedigree of X-linked syndromic deafness derives from partial Xp duplication, which will guide further research to identify the breakpoint of this abnormal chromosome.