应用基因内探针及微小卫星DNA多态性分析脆性X综合征家系

GENE ANALYSIS OF A FRAGILE X FAMILY USING INTRAGENIC PROBES AND MICROSATELLITES REPEATS

用位于脆性X综合征基因(FMR-1)内的探针StB12.3和StB12XX对一脆性X家系分支进行了DNA分析。结果表明,探针StB12.3与EcoRI+Eag I酶消化结合可以鉴别出该家系中具有完全突变的患者。而探针StB12XX与Bcl I消化结合则更易于判断前突变的长度变化,区分携带者。进一步应用PCR方法扩增距脆性X位点150kb的双核苷酸重复顺序,DNA多态性分析表明,在该家系中脆性X突变与f型定位基因紧密连锁。

The intragenic (FMR-1)probes were used for DNA analysis in a sub fragih X family. With probe StB12. 3 to EcoRI+Eag I digests, the full mutation of affected individuals was detectable, but for some carriers with smaller premutation, the combination of probe StB12XX and Bel I digest was probably more efficient. The polymorphism of dinucleotide repeat, DXS548, which is approximately 150kb to the fra (X) site was further studied. It was revealed that the fragile X mutation was linked to f allele (204bp) in this family. This made the screening of the big family easier.