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目的对2名来自不同家系的肾上腺脑白质营养不良携带者所怀胎儿进行产前分子诊断。方法在采用STR位点分析方法排除母体基因组DNA污染后,应用扩增阻滞突变系统和DNA斑点杂交的方法对胎儿1羊水基因组DNA进行检测,应用PCR-RFLP和DNA序列测定对胎儿2羊水基因组DNA进行分析。结果在针对R617G突变的扩增阻滞突变系统中,当使用突变引物时,从胎儿1羊水DNA、胎儿1母亲基因组DNA均扩增出185bp的预期特异性条带,而胎儿1父亲和对照则未扩出。在斑点杂交反应中,应用R617G突变型探针时,只有胎儿1羊水细胞及其母亲外周血基因组DNA出现特异性显色斑点。在第2个家系中,先用PCR扩增出横跨P534R突变位点的基因组DNA片段(506bp),应用HaeⅡ酶切此产物,胎儿2以及其父亲、无关对照均未见切割,其母亲的部分产物被切割成396bp和110bp两个片段。对此PCR产物进行DNA序列测定,未在胎儿2中检测出P534R突变。结论胎儿1带R617G突变,为肾上腺脑白质营养不良半合子;胎儿2不带P534R突变,为正常半合子。
OBJECTIVE: To conduct prenatal molecular diagnosis of fetuses from 2 carriers of adrenoleukodystrophy from different families. Methods After genomic DNA contamination was eliminated by STR loci analysis, genomic DNA of fetus 1 was detected by PCR amplification and DNA blotting. PCR-RFLP and DNA sequencing were used to detect fetal genomic DNA DNA for analysis. Results In the amplification-blocking mutation system targeting R617G mutation, 185 bp of expected specific bands were amplified from fetal 1 amniotic fluid DNA and fetal 1 maternal genomic DNA, respectively, while fetal 1 father and controls Not expanded. In the dot blot hybridization, only R627G mutant probe, only fetal 1 amniotic fluid cells and their mothers peripheral blood genomic DNA showed specific color spots. In the second pedigree, a genomic DNA fragment (506 bp) spanning the P534R mutation site was first amplified by PCR. This product was digested with HaeII, and fetal 2 and its father, unrelated controls, were not cut, and their mothers Some products were cut into two fragments of 396 bp and 110 bp. The PCR product was subjected to DNA sequencing and no P534R mutation was detected in fetus 2. Conclusion Fetal 1 with R617G mutation is adrenoleukodystrophy hemizygous; fetus 2 without P534R mutation is normal hemizygous.