【摘要】 为了探讨简便、快速、准确、价廉的脆性X综合征的诊断方法,对6个智能低下家系进行了细胞遗传学检查,以及PCR直接扩增FMR15′端(CGG)n重复序列、RT-PCR扩增FMR1基因的cDNA序列的分子遗传学检查。A家系先证者脆性X染色体高表达(35 273),分子遗传学检查证实为脆性X综合征全突变患者;B家系先证者及其母亲无脆性X染色体表达,分子遗传学检查证实为非脆性X综合征患者;C家系的男性胎儿脆性X染色体表达(5 93),先证者及其母亲未发现脆性X染色体,分子遗传学检查证实男性胎儿为脆性X综合征全突变患者,其母亲为前突变携带者,哥哥为嵌合体患者;D家系先证者脆性X染色体高表达17%,其姐姐脆性X染色体5%,分子遗传学检查证实先证者为脆性X综合征全突变患者,其姐姐为嵌合体患者;E家系先证者及其母亲,F家系先证者发现可疑脆性X染色体,分子遗传学检查证实为非脆性X综合征家系。结论:PCR直接扩增FMR1基因(CGG)n重复序列联合RT-PCR扩增FMR1基因cDNA序列简便、快速、价廉。可用于脆性X综合征的筛查、诊断及产前诊断,有推广应用价值。更多还原

【Abstract】 In order to obtain a simple,fast,accurate and low-cost diagnosis method of fragile X syndrome,cytogenetic tests and molecular genetic tests were carried out with direct amplification of (CGG)n repeat sequence in 5′ terminal of FMR1 gene by PCR and the cDNA sequence of FMR1 by RT-PCR from six mental retardation pedigrees.The proband of pedigree A with highexpression of fragile X chromosome(35/273) was detected to be a full mutation patient of fragile X syndrome by the molecular genetic test.There is no expression of fragile X chromosome in the proband and his mother of pedigree B,which was futher confirmed as a non-fragile X pedigree by the molecular genetic test.A male foetus of the pedigree C has fragile X chromosome(5/93),but the proband and his mother has no fragile X chromosome.By further detection using molecular genetic test,the male foetus is a full mutation patient of fragile X syndrome,his mother is a permutated carrier,and his brother is a mosaic patient.The proband of pedigree D has high expression of fragile X chromosome(17%),his sister also has expression of fragile X chromosome(5%).By further detection with molecular genetic test,the proband is a full mutation patient of fragile X syndrome,and his sister is a mosaic patient.The probands of pedigrees E and F of the mother were found with suspicions fragile X chromosome,being confirmed as the non-fragile X pedigrees by the molecular genetic test.The conclusion is that the analysis test with direct amplification of 5′(CGG)n repeat sequence and cDNA sequence in FMR1 gene is simple,fast,low-cost and can be applied in screening,diagnosis and prenatal diagnosis of fragile X syndrome.更多还原