Phenotype and genotype analysis of in herited dysplasminogenemia caused by plasminogen Ala601Thr mutation

Abstract

Objective To detectthe phenotype and gene mutations underlying aninherited dysplasminogenemia pedigree and search the virulence gene. Methods The peripheral venous blood samples of the proband and his family members(fourteen subjects of three generations in total)were collected, and their prothrombin time(PT), activated partial thromboplastin time(APTT), thrombin time(TT), fibrinogen(FIB), fibrinogen degradation products(FDP), D-dimmer(D-D)weretested on a STAGO analyzer, the plasminogen activity(PLG: A)and plasminogen antigen(PLG: Ag)were analyzedby thechromogenic substrate assay and rocket immunoelectrophoresis, respectively. All 19 exons, 5' and 3' untranslated regions of PLG were amplified with PCR. Direct DNA sequencing was used to analyze the amplified products, which were confirmed by backward sequencing. Three bioinformatics online softwares(SIFT, PolyPhen-2 and MutationTaster)were used to forecast the possible impact of the mutations on the protein function. At last, the model analysis of mutate site was taken on a Swiss-Pdb Viewer software. Results The PLG: Avalue of the proband and other 6 family members were decreased to the half, while the PLG: Ag was normal. The D-D and FDP value of the proband, his grandma and father were slightly higher. DNA sequencing has revealed that the proband and the other 6 members of this family had the same mutation of g. 38829G>A in exon 15, leading to the missense mutationp.Ala601Thr.The results of bioinformatics softwares showed that the mutation could affect the thePLGfunction. Protein model analysis indicated that the hydrophobic interaction force and hydrogen bond between the amino acids were changed, which might affect the stability of the PLG.In addition, all the members of this family take the heterozygous SNP of g. 2501C>A in the 5'UTR. Conclusions The p. Ala601Thr found in the inherited dysplasminogenemia pedigree in the exon 15 was responsible for the reduced PLG: A of the family, the dysplasminogenemia and this mutation were both reported for the first time in China.(Chin J Lab Med, 2016, 39: 366-371) Key words: Mutation, Missense; Plasminogen; Polymor phism, single nucleotide