| Objective: FXIIID is an extremely rare serious bleeding disorder.The purpose of this study is to clarify the clinical characteristics and gene mutations of FXIIID,provide systematic clinical consultation for patients,and identify the pathogenic mechanism of new gene mutations.Methods:(1)Explain the clinical characteristics of the disease through common laboratory inspections and special tests,and specifically use thrombin generation experiments for detection;(2)Use next generation sequencing to identify mutation sites and verify by Sanger sequencing;(3)The potential pathogenic mechanism of the mutation site was predicted by bioinformatics analysis;(3)splice site mutation was verified by minigene;(4)the use of CHX and si RNA-UPF1 recovery experiments to investigate the presence of truncated proteins and m RNA degradation.Results:(1)Patients with FXIIID have a tendency to bleed,all four coagulation results are normal,and the level of FXIII Ag is extremely low;(2)The thrombin generation ability of patients with FXIIID is enhanced compared to normal people;(3)A deep intron mutation,c.799-12G> A,is found;(4)the m RNA expressed by the vector containing c.799-12G> A mutation contains 10 bp from intron 6;(5)the expression of the protein encoded by the mutant gene increases after NMD is inhibited.Conclusion: FXIIID is a severe bleeding disease,specifically manifested as neonatal umbilical cord bleeding,deep soft tissue hematoma,and central nervous system bleeding.In this study,a new intron mutation c.799-12G> A was reported for the first time,and it was confirmed that the mutation was a splice site mutation,which caused 10 bp of intron 6 to stay in the m RNA,which caused a frame shift to generate PTC.NMD is triggered.At the same time,studies have shown that the thrombin generation ability of patients with factor 13 deficiency is significantly improved,which may explain that factor 13 deficiency is prone to form thrombus in plasma supplementation therapy. |
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