Phenotype and gene mutation analysis of two compound heterozygous mutations resulting in families with inherited coagulation factor V deficiency
ZHENG Zhou, XU Qiyu, ZHOU Xingxing, WANG Mingshan,XIE Yaosheng
Center of Laboratory Medicine, the First Affiliated Hospital of Wenzhou Medical University,Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou 325015, China
ZHENG Zhou,XU Qiyu,ZHOU Xingxing, et al. Phenotype and gene mutation analysis of two compound heterozygous mutations resulting in families with inherited coagulation factor V deficiency[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2023, 53(12): 947-953.
Abstract：Objective: To analyze the coagulation index and genotype of two patient with hereditary coagulation Factor V (FV) deficiency by compound heterozygous mutations and their family members, and to explore their molecular pathogenesis. Methods: The blood coagulation indexes such as Plasma FV activity
(FV:C) and FV antigen (FV:Ag) in the peripheral blood of each family member were measured by the onestage clotting method. All exons and their flanking regions of the F5 gene were amplified by PCR and then sequenced. The impact of mutations on protein function was analyzed by Bioinformatics software. The spatial structure changes of FV proteins were analyzed by PyMOL software before and after mutations. The function of the mutant protein was analyzed by the Calibrated automated thrombogram. Results: Phenotypic testing showed that both probands had a decrease in FV:C and FV:Ag simultaneously, manifesting as type I of the FV deficiency. Genetic analysis showed that the proband A had c.332G>T heterozygous missense mutation (p.Ser111Ile) in exon 3 and c.6665A>G heterozygous polymorphism (p.Arg2222Gly) in exon 25; the proband B had c.286G>C heterozygous missense mutation (p. Asp96His) in exon 3 and c.2393-2393delC heterozygous deletion mutation (p.Pro798Leufs*13) in exon 13. Bioinformatics analysis showed the p.Ser111Ile mutation and the p.Pro798Leufs*13 mutation were pathogenic mutations. Protein model analysis showed that p.Ser111Ile mutation could affect the structure of hydrogen bonds between amino acids. The truncated protein were produced by a p.Pro798Leufs*13 mutation. The thrombin generation test showed that the clotting function of proband A and B had been affected. Conclusion: These four mutations may be responsible for the reduction of FV level in two families. Moreover, the p.Ser111Ile mutation is a rarely reported.
