Abstract：
Inferior vena cava thrombosis (IVCT) is rare. Thrombophilia is one of the important risk factors. It is also uncommon for gene mutations in F9 gene to cause thrombosis but not hemorrhage. A 35-year-old male patient was admitted to our department with left lower limb swelling without an obvious cause for 1 day. Through contrast-enhanced computed tomography and color Doppler ultrasound, he was found to have lower extremity deep vein thrombosis, IVCT and pulmonary embolism. Through whole-exome sequencing analysis, he was found to carry a 925.7 kb duplication (chrX:137939698-138865419, hg19) encompassing ATP11C , SRD5A1P1 , MCF2 , FGF13 and F9 genes. This duplication of F9 gene was not detected in his parents. Other thrombophilic genes defects were not found. The factor IX activities of this patient, his father and mother were 194, 70 and 148, respectively. He was treated with catheter-directed thrombolysis, AngioJet-assisted pharmaco-mechanical thromboectomy and manual aspiration thromboectomy. Complete recanalization of left femoral, iliac veins and inferior vena cava was achieved. F9 gene duplication is a rare mutation, which can induce multiple venous thrombosis through increasing the activity level of factor IX in plasma. IVCT is a serious type of venous thrombosis. Personalized intervention treatment plans should be developed based on the different clinical characteristics of each case to achieve a higher benefit-risk ratio.
摘要：
下腔静脉血栓形成（IVCT）很少见。血栓形成是重要的危险因素之一。F9基因中的基因突变引起血栓形成而不是出血也不常见。一名35岁的男性患者因左下肢肿胀而入院1天，无明显原因。通过对比增强计算机断层扫描和彩色多普勒超声，他被发现有下肢深静脉血栓,IVCT和肺栓塞。通过全外显子组测序分析,他被发现携带925.7kb的复制品(chrX:137939698-138865419，hg19)，包括ATP11C，SRD5A1P1、MCF2、FGF13和F9基因。在他的父母中未检测到F9基因的这种重复。未发现其他嗜血栓基因缺陷。该患者的因子IX活动，他的父亲和母亲分别是194、70和148。他接受了导管溶栓治疗，血管喷射辅助药物机械血栓切除术和手动抽吸血栓切除术。左股骨完全再通，实现髂静脉和下腔静脉。F9基因重复是一种罕见的突变，可以通过增加血浆中因子IX的活性水平来诱导多次静脉血栓形成。IVCT是一种严重的静脉血栓形成。应根据每个病例的不同临床特征制定个性化的干预治疗计划，以实现更高的受益风险比。
