血友病携带者与产前基因诊断

目的建立1种简便、快速的血友病携带者检测与产前诊断体系。方法对38个血友病A家系,用长链PCR及序列特异PCR作F8基因内含子22及1倒位检测;有家族史家系可联合F8基因内外的8个多态性位点进行遗传连锁分析,DXS 52(ST14)位点多态性以PCR产物凝胶电泳法检测,7个STR位点(F8C ivs13、CA22、DXS15、DXS9901、G6PD、DXS1073、DXS1108)的多态性以多重荧光PCR法检测,产前诊断加用性别位点(Amelo);对于散发家系,通过直接核苷酸测序查找先证者的基因突变,继而对家系女性成员作携带者与产前诊断。对12个血友病B家系采用直接核苷酸测序法确定基因突变,多重荧光PCR法检测F9基因外6个STR位点(DXS1192、DXS1211、DXS8094、DXS8013、DXS1227、DXS102)的多态性。结果38个血友病A家系中,10名先证者的F8基因内含子22倒位检测为阳性,1例先证者为F8基因内含子1倒位阳性,对于有家族史的家系,综合应用倒位检测和遗传连锁分析,携带者与产前诊断率均为100%;4个散发家系均可找到致病突变;38个血友病A家系的携带者及产前诊断总诊断率为94.81%。12个血友病B家系中有10个家系通过直接测序可找到突变,联合F9基因外6个STR位点对血友病B家系的遗传连锁分析的可诊断率为96.88%。结论F8基因内含子22及1倒位筛检联合F8基因内、外多个位点的遗传连锁分析可以进行血友病A的携带者及产前诊断;直接核苷酸测序可确定F9基因突变,而联合基因外多个多态性位点检测并进行遗传连锁分析,是血友病B携带者检测与产前诊断的简便、快速的方法。

Carrier detection and prenatal diagnosis of haemophilia

Objects To establish a simple,rapid carrier detection and prenatal diagnosis system for hemophilia.Methods Thirty-eight HA families were tested for the intron 22 and 1 inversions in factor VIII gene by LD-PCR and PCR.The remaining inversion negative families,but with family history,were screened using linkage analysis with 8 combined polymorphic markers,including St14,F8IVS13,CA22,DXS15,DXS9901,G6PD,DXS1073,and DXS1108.For sporadic families,the whole gene sequencing was applied directly to detect the mutation.For HB families,linkage analysis with 6 STRs,including DXS1192,DXS1211,DXS8094,DXS8013,DXS1227 and DXS102,was applied to get quick diagnostic information.The whole gene sequencing was used to get the final diagnosis.The rapid fluorescent PCR combined with polymorphism markers were applied for linkage analysis in HA and HB families,respectively.As soon as the pregnancy was identified,additional Amelo site detection would be performed.Results In 38 HA families,introns 22 and 1 inversions were found in 10 and 1 probands,respectively.The diagnostic rates of St14,F8IVS13,CA22,DXS15,DXS9901,G6PD,DXS1073 and DXS1108 were 61.11%,76.67%,71.43%,70.59%,62.50%,10.00%,75.00% and 50.00%,respectively.Combining inversion detection and linkage analysis,the diagnostic rate of carrier detection and prenatal diagnosis of families with HA family history were both 100%.One intron 22 inversion and 3 mutations were detected in 4 sporadic families.The total diagnostic rate of 38 HA families was 94.81%.And 10 mutations were detected in the 12 HB families.Combined with the linkage analysis,the total diagnostic rate was 96.88%.Conclusions Introns 22 and 1 inversion screening combined with the linkage analysis,using the highly informative polymorphic markers,can be used for carrier detection and prenatal diagnosis in Chinese HA families.The direct sequencing of FⅨ with the linkage analysis can be successfully applied for carrier detection and prenatal diagnosis of HB families.