7个血友病A家系基因型与临床表型分析

Relationship between genotypes and clinical phenotypes in patients from 7 hemophilia A families

摘要:

目的 确定各家系凝血因子Ⅷ(F Ⅷ)基因突变类型,了解基因突变与临床表型的关系。方法 对7 个家系患者进行活化部分凝血酶原时间(APTT)及凝血因子Ⅷ凝结活性(F Ⅷ :C)检测,再采用PCR 方法对7 个血友病A家系患者进行内含子22、内含子1 倒位检测,对检测结果阴性患者采用直接测序法确定基因突变类型,并对家系相关成员进行相应位点的扩增与测序。结果 8 例血友病A患者APTT 为91.6~131 s,F Ⅷ :C 为0.8%~2%,基因检测结果显示8 例患者中未检出内含子22 倒位,仅检出1 例内含子1 倒位。余7 例血友病A 患者中,共检出5 种基因型,其中6例位于外显子14,1例位于外显子23,均为单碱基突变;有1 例检出基因型为p.His1202LeufsX16(c.3666delA),经检索为新突变。结论 F Ⅷ突变热点区域位于外显子14,新突变p.His1202LeufsX16 的发现丰富了F Ⅷ基因突变数据库。

Abstract:

Objective To study the mutation types of factor VIII (FVIII) gene in patients from 7 hemophilia A (HA) families and the relationship between FVIII gene mutations and clinical phenotypes.Methods A total of 8 patients from 7 HA families were recruited. The activated partial thromboplastin time (APTT) and factor VIII coagulant activity (VIII:C) in these patients were measured. Polymerase chain reaction (PCR) was performed to analyze FVIII gene intron 1 and 22 inversions. For patients without the FVIII intron inversions, direct sequencing was performed to determine their mutation types and other related members of their families were also tested by PCR and sequencing to analyze the corresponding mutation sites.Results The ranges of APTT and VIII:C of the 8 patients were 91.6-131 seconds and 0.8%-2%, respectively. FVIII gene intron 22 inversion was not detected, while intron 1 inversion was detected in one patient. There were 5 types of mutations in FVIII gene detected in the remaining 7 patients, including 6 patients with mutations in exon 14 and 1 patient with mutation in exon 23; all of the 5 types of mutations were single nucleotide mutations. Among the detected mutations in FVIII gene, p.His1202LeufsX16 (c.3666delA) detected in one patient was found to be a previously unreported mutation in FVIII gene.Conclusions FVIII gene exon 14 is a hot-spot mutation region and p.His1202LeufsX16 is found to be a novel mutation in FVIII gene.