联合运用St14(DXS52)位点VNTR和 FⅧ基因内的(CA)n重复多态性诊断甲型血友病

目的　提高甲型血友病 (hemophilia A,HA)家系成员基因诊断及产前基因诊断的准确性和可诊断率。方法　采用 St14 (DXS5 2 )位点的可变串联重复序列和 F 基因第 13内含子的 (CA) n重复多态性连锁分析对 HA家系进行间接基因诊断。结果　单用上述 2个多态位点中的 1个对 9个 HA家系进行连锁分析 ,可诊断率均为 6 6 .7% ,联合 2个多态位点 ,可诊断率则提高到 88.9% ,完成了 4个家系的产前基因诊断 ,并监测到 1例单用 St14位点的可变串联重复序列多态连锁分析可能发生的产前诊断的误诊。结论联合采用上述 2个多态位点可以对近 90 %的 HA家系作出快速、准确的基因诊断和产前基因诊断。

Diagnosis of hemophilia A by a combination of St14(DXS52) VNTR polymorphism and (CA)n repeat polymorphism within FⅧ gene

OBJECTIVE: To improve the accuracy and the diagnostic rate of gene diagnosis and prenatal gene diagnosis for hemophilia A (HA) families. METHODS: Linkage analysis was performed by using St14(DXS52) VNTR polymorphism and intron 13 (CA)n repeat polymorphism of the factor VIII gene among HA families for indirect diagnosis. RESULTS: The diagnostic rates using linkage analysis based upon one of the above mentioned two polymorphic loci among 9 HA families were 66.7% and 66.7%, respectively. The diagnostic rate rose to 88.9% by using a combination of the two polymorphic loci. Prenatal gene diagnoses were performed for 4 HA families. A wrong prenatal diagnosis which may happen when linkage analysis was performed by using only St14 VNTR was monitored. CONCLUSION: The rapid and accurate gene diagnosis and prenatal gene diagnosis could be performed by a combination of the two polymorphic loci for about 90% HA families.