[FⅨ gene all exons sequencing technology in hemophilia B gene carriers detection and the application of prenatal gene diagnosis].

To establish a feasible protocol to provide genetic diagnosis and prenatal diagnosis in Chinese hemophilia patients and their relatives by direct exon sequencing.In our study, genetic diagnosis was performed on 5 unrelated families with informed consent, which included 3 pregnant women who asked for prenatal diagnosis. Umbilical cord blood was obtained from 2 fetuses and amniotic fluid from another fetus. After extraction of the genomic DNA, all of the exons, exon-intron boundaries and their flanks of FⅨ gene were amplified by polymerase chain reaction (PCR). PCR products were detected through direct-sequencing.Sequence analysis indicated that the patients and carriers from 5 families have the pathogenic mutations,c.1022G>A (p.R341Q), c.484 C>T (p. R162X), c.1135C>T (p.R379X), c.799C>T (p.H267Y), c.1232G＞T (p.S411I), respectively. Except c.484 C>T (p. R162X), 4 of the 5 mutations were reported firstly in Chinese population. During prenatal diagnosis, one of the fetuses was found to be affected with c.484C>T; p.R162X. The remaining two fetuses were diagnosed as normal, the results of which were later verified by post-birth diagnosis, and factor FⅨ activities in plasma was 52.7% and 76.2%, respectively.In the quest of strict quality control, exon sequence on FⅨ gene was a rapid and accurate method for genetic diagnosis and prenatal diagnosis of hemophilia B.目的 探索应用FⅨ基因全外显子测序技术进行血友病B(HB)基因携带者检测和产前基因诊断。方法 在取得5个无血缘关系的汉族HB家系成员知情同意后,采集相关家系成员标本。3个产前诊断标本中,2例为胎儿脐血标本,1例为羊水标本。从标本中提取基因组DNA,通过PCR扩增FⅨ基因所有外显子及其侧翼序列,将产物进行全外显子直接测序。结果 5个家系的HB患者以及FⅨ基因携带者共检出5种突变：c.484 C>T (p.R162X)、c.1022G>A (p.R341Q)、c.1135C>T (p.R379X)、c.799C>T (p.H267Y)和c.1232G>T (p.S411I)。在产前诊断中,发现1例c.484 C>T (p.R162X)突变,另2例未检出FⅨ基因突变的胎儿出生后血浆FⅨ促凝活性分别为52.7%和76.2%。结论 首次报道中国汉族HB家系FⅨ基因c.1022G>A (p.R341Q)、c.1135C>T (p.R379X)、c.799C>T (p.H267Y)和c.1232G>T (p.S411I)突变;在严格的质量控制下,FⅨ基因全外显子直接测序是一种快速准确的诊断HB基因携带者及产前基因诊断的方法。