血友病A患者凝血因子Ⅷ基因内含子1及22倒位分析

Intron 1 and 22 inversions in factor vm gene in patients with haemophilia A

目的 对血友病A（HA）患者及其家系携带者进行凝血因子Ⅷ（FⅧ）基因内含子1及22倒位分析，并探讨其与FⅧ抗体产生的相关性。方法对157例HA患者进行FⅧ活性（FⅧ：C）及FVH抗体检测；同时采用双管多重PCR及长距离PCR（LD—PCR）技术对其中81例HA患者进行FⅧ内含子1及内含子22倒位分析；并对其中6例患者进行家系调查。结果81例HA患者中3例为内含子1倒位，均为重型，占重型HA的4．6％（65例中3例）；内含子1倒位患者中1例为FⅧ抗体阳性。用该基因信息对1个内含子1倒位患者家系的2名女性进行了检测，1例为携带者，1例为非携带者。81例HA患者中25例为内含子22倒位，均为重型，占重型HA的38．5％（65例中25例），内含子22倒位患者中发现1例为FVI抗体阳性。用该基因信息对5个内含子22倒位患者家系的9名女性进行了检测，7例为携带者，2例为非携带者。结论内含子1倒位是继内含子22倒位外导致重型HA的另一重要分子发病机制。FⅧ内含子倒位检测不仅可用于血友病直接基因诊断、进行家系调查；同时还可纠正表型分型的偏差。FVH内含子1和内含子22倒位可能是抗体产生的高危因素之一。

Objective To analyze intron 1 and 22 inversions in factor Ⅷ （FⅧ） gene in hemophilia A（HA） patients and and their families and to investigate the correlation between intron inversion and FⅧ antibody. Methods All patients were detected FⅧ： C and FVⅧ antibody. In addition, 81 unrelated HA patients were directly detected by multiplex PCR and long-distance PCR for intron 1 and 22 inversions in FⅧ gene. Pedigree investingation for some patients were conducted. Results In 81 unrelated HA patients, 3 severe cases were found intron 1 inversion which accounted for 4.6% of total 65 severe cases. Of the 3 cases, one was FⅧ antibody positive. Two female family members of a intron 1 inversion patient were identified as one carrier and one non-carrier. Twenty five of 65（38.5%） severe cases were found intron 22 inversion. Of the 25 cases 1 was Fvm antibody positive. Nine female members in 5 HA families which had patients with intron 22 inversion were identified as 7 carries and 2 non-carriers. Conclusion Besides intron 22 inversion, intron 1 inversion was another important molecular defect in resulting in severe HA. Intron inversion analysis can also be used for deviation rectification of experiment grouping in HA patients. Intron 1 and 22 inversions may be one of the higher risk factors for resulting in FⅧ antibodies.