Abstract:

Objective: To develop an accurate, simple and practical method for detecting hereditary risk factors of thrombophilia, which can be used for early diagnosis and treatment guidance in Chinese thrombophilia patients. Methods: Altogether 246 patients with venous thrombosis at our hospital were enrolled. The clinical data and family history were collected. Phenotypic examinations were performed. Eighteen candidate genes related to thrombosis were selected to compose a gene panel through literature searching. Point mutation, small deletion/insertion and copy number variations of this panel were detected by next-generation sequencing and CNVplex^® technique. Results: Of the 246 patients with venous thrombosis, 159 patients were identified as having gene mutations. The mutation detection rate was 64.6%. Among them, 69.2% carried a single mutation, 13.2% carried compound heterozygous mutation in one gene, and 17.6% carried mutations of at least two genes. Of the 159 patients carrying gene mutations,144 patients carried mutations of anticoagulant protein genes(SERPINC1, PROS1 and PROC), while 31 patients carried mutations of other 10 genes (F2, F5, F9, F12, PROCR, THBD, SERPIND1, PLG, ADAMTS13 and TFPI), in which some mutations (F2 R384Q and F9 R596Q) had been confirmed to be associated with venous thrombosis. Copy number detection showed that 19 patients had copy number variations, mainly in PROCR and PROS1 genes. In addition, 40 of 61 patients with acquired thrombosis risk factors (antiphospholipid syndrome, surgery or pregnancy, etc.) carried hereditary thrombosis risk factors. Of the 56 patients with normal phenotypic results, 20 of them carried pathogenic thrombotic mutations revealed by genetic analysis. Moreover, of the 72 patients who were in the acute stage of thrombosis or during anticoagulants treatment thus could not take phenotypic examination, 32 were identified as having pathogenic thrombotic mutations. Conclusions: The hemophilia gene detection panel established can screen the hereditary thrombosis risk factors more quickly, effectively and accurately. It is necessary to carry out genetic analysis in patients with acquired risk factors. According to the results of gene analysis, clinicians can provide appropriate preventive treatment to prevent the occurrence or recurrence of thrombosis, and to reduce the occurrence of post-thrombotic syndrome, and is worthy of application in clinical practice.

Key words: Thrombophilia, Venous thromboembolism, Second generation sequencing, Copy number variations