产前基因检测杜氏肌营养不良

Prenatal gene diagnosis for Duchenne muscular dystrophy

目的产前基因检测杜氏肌营养不良症(Duchenne muscular dystrophy,DMD)家系胎儿。方法利用性别决定基因SRY引物PCR和羊水细胞培养染色体核型分析确定3例DMD家系胎儿性别,采用mPCR技术对3个DMD家系成员外周血及胎儿羊水和脐静脉血进行DMD基因内18个外显子位点扩增,STR-PCR结合聚丙稀酰胺凝胶技术对DMD基因3′端及基因内的44、45、49、50内含子的(CA)n短串联重复序列引物进行扩增,进行家系连锁分析和产前基因诊断。结果共检出4例胎儿,其中2例单胎和1例双胎之甲胎为男性,之乙胎为女性。3个DMD家系2个检出为非缺失型,1个为缺失型。4例胎儿均继承了与同代先证者相同的母源致病单体型,除1例双胎之女胎为风险基因携带者外,其余3例男胎均为DMD风险胎儿,3例患儿母亲均为杂合型。结论STR多态连锁分析不仅适用于常见缺失突变检测未发现缺失的DMD患者,同样适用于缺失型DMD患者的产前基因检测。

Objective To establish a basis for genetic counseling and prenatal gene diagnosis of Duchenne muscular dystrophy （DMD）. Methods Three pregnant DMD carriers visited our department and their fetal gender was determined by sex determining gene primer polymerase chain reaction （PCR） and cell karyotyping of amniotic fluid. The genomic DNA was extracted from the peripheral blood of the family members with DMD and fetal amniotic fluid or fetal umbilical vein blood. Then multiplicitas prime PCR and polyacrylamide gel method were used to analyze the polymorphism of the （CA）n short tandem repeat （STR） in 3＇ end and in the introns 44, 45, 49, 50 of DMD gene. Results In the 4 fetuses, two singleton fetus and one of the twins were male, the other of twins was female. Gene deletion occurred in one pedigree and non-gene deletion in the other two pedigrees. Four fetuses had the same haploid of proband inherited from their mothers. The female fetus of the twins was risk DMD gene carrier, and the other three male fetuses were DMD risk ones. The mothers of three probands were heterozygous. Conclusion STR polymorphism-based linkage analysis is suitable for DMD patients no matter who had not been found common deletion or not.