用RFLP连锁分析法对一个Becker型肌营养不良症家系突变基因的研究

STUDY ON MUTATION GENEORIGIN IN A BECKER MUSCULAR DYSTROPHY FAMILY USING RFLP LINKAGE METHOD

作者用DMD/BMD基因位点内部DNA探针PERT87系列及XJ2.3和侧翼连锁探针754对一个Becker型肌营养不良症家系进行了RFLP单体型连锁分析,结果发现该家系三个同胞患儿携带致病基因的那条X染色体来自他们表型正常的外祖父。椐此推论,患儿外祖父在其精子发生中产生了一次EMD位点的基因突变,通过患儿母亲将BMD致病基因传递到患儿这一代,因此,患儿姨母携带致病基因的风险仅相当于该位点的自然突变率。研究结果表明,RFLP单体型连锁分析有助于追溯到BMD家系中突变基因的起源,从而对这些家系的遗传分析起重要的指导作用。

Restriction fragment length polymorphism (RFLP)haplotype linkage analysis was performed in a Eecker muscular dystrophy (BMD)family with intragenic DNA probes PERT 87-8,PERT 87-15, XJ 2.3 and flanking probe 754. The result revealed that the X chromosome of three affected boys which carried the mutation for BMD originated from their maternal gradfather. Threrefore, the mutation most likely had occured in his sperm and the risk of the maternal aunt being carrier status is very low, Our finding strongly supggests that the RFLP approach is useful in tracing the origin of BMD locus mutation in the families in which affected boys are not present in more than one generation and helpful in genetic consultation.