OBJECTIVETo identify the antithrombin (AT) phenotype and gene mutation of a kindred with hereditary antithrombin deficiency.

METHODSPlasma AT activity and AT antigen level of the propositus and his kindred members were determined with chromogenic substrate method and immunoassay, respectively. All the seven exons and intron-exon boundaries of antithrombin gene were analyzed by PCR and direct sequencing of amplified PCR products from the propositus.

RESULTSThe propositus AT antigen level was normal but his AT activity was only 65% of normal value suggesting that he had type II AT deficiency. A heterozygous G13830A mutation in exon 6 resulting in Arg393His missense mutation in his AT polypeptide was identified in the propositus. The same phenotype and gene mutation were found in other 3 kindred members.

CONCLUSIONThe type II AT deficiency found in this kindred is caused by heterozygous G13830A mutation in AT gene.

Adult ; Antithrombin III ; genetics ; metabolism ; Antithrombin III Deficiency ; genetics ; Heterozygote ; Humans ; Male ; Mutation ; Pedigree

OBJECTIVETo identify the clinical phenotype and gene mutation in two kindreds with type I inherited antithrombin (AT) deficiency.

METHODSThe coagulation and anticoagulation testing and thrombophilia screening were used for phenotypic diagnosis and immunonephelometry and chromogenic assay for plasma level of AT antigen (AT:Ag) and AT activity (AT:A), respectively. All of the seven exons and intron-exon boundaries and untranslation regions of AT gene were amplified by PCR, and the PCR products analysis was by direct sequencing. The corresponding gene sites of the two family members and healthy individuals were detected according to the gene mutation sites.

RESULTSThe plasma levels of AT:Ag of proband 1 and proband 2 were 126 mg/L and 117 mg/L, and AT:A was 49% and 48%, respectively. Heterozygotic deletion of 3239-3240delCT in proband 1 and nonsense mutation 3206A-->T (K70Stop) in proband 2 were rchaacterized in exon 2 of AT gene. And some of their family members were also detected with the heterozygotic gene mutation.

CONCLUSIONType I inherited antithrombin deficiency of the two probands were caused by AT gene mutation 3239-3240delCT and 3206A-->T (K70Stop).

Antithrombin III Deficiency ; genetics ; Heterozygote ; Humans ; Mutation ; Pedigree ; Phenotype

OBJECTIVETo study the molecular mechanisms of inherited antithrombin (AT) deficiency caused by AT L99 mutation.

METHODSWild type (WT), L99V, L99A, L99I and L99S AT were purified from drosophila expression system. The binding capacity of AT and the low molecular weight heparin sodium was analyzed by the heparin binding assay. Surface plasmon resonance (SPR) was used to detect the binding ability of AT to thrombin (FIIa) or AT to coagulation factor Xa (FXa). The activity of AT(AT∶A)was detected by chromogenic assay.

RESULTSThe purified WT and mutant AT were at the same size. No additional band was observed by coomassie blue staining and western blot assay. Compared to the WT AT, the binding abilities of the low molecular weight heparin sodium to the AT L99V, L99A, L99I and L99S were (44.8±3.6)%, (118.9±14.0)%, (15.2±8.8)%, and(23.0±8.2)%, respectively. The binding abilities of FIIa to AT L99V, L99A, L99I and L99S were 13%, 57%, 3%, and 29%, while the binding of FXa to AT L99V, L99A, L99I and L99S were 7%, 51%, 1%, and 25%. The AT∶A of WT, L99V, L99A, L99I and L99S AT were 146.5%, 21.4%, 120.9%, 10.8%, and 39.0%, respectively.

CONCLUSIONThe binding abilities of AT to heparin, FIIa and FXa were damaged by the L99 mutation, which resulted in decreased AT∶A and inherited AT deficiency.

Amino Acids ; genetics ; Animals ; Antithrombin III ; genetics ; Antithrombin III Deficiency ; genetics ; Antithrombins ; Drosophila ; Factor Xa ; genetics ; Genetic Vectors ; Humans ; Mutation

OBJECTIVE: To analyze the phenotype and genotype of a patient affected with inherited antithrombin deficiency. METHODS: All exons and exon-intron boundaries of the AT genes were subjected to PCR amplification and Sanger sequencing. The influence of variants on the disease was predicted using bioinformatic software (MutationTaster). RESULTS: The results of all coagulation tests were normal, though the antithrombin activity and antigen content of the proband and his father have decreased significantly (34%, 48% and 12.97 mg/dL, 15.60 mg/dL, respectively). His mother was normal. Genetic analysis revealed that the proband and his father both carried a heterozygous g.2736dupT variant of the AT gene. Bioinformatic analysis suggested that the variant may be pathogenic. CONCLUSION The proband and his father both had type I hereditary antithrombin deficiency caused by a g.2736dupT variant of the AT gene. The variant was unreported previously.
Antithrombin III/genetics* ; Antithrombin III Deficiency/genetics* ; DNA Mutational Analysis ; Genetic Testing ; Heterozygote ; Humans ; Male ; Mutation ; Pedigree

Antithrombin and protein C are two crucial members in the anticoagulant system and play important roles in hemostasis. Mutations in SERPINC1 and PROC lead to deficiency or dysfunction of the two proteins, which could result in venous thromboembolism (VTE). Here, we report a Chinese 22-year-old young man who developed recurrent and serious VTE in cerebral veins, visceral veins, and deep veins of the lower extremity. Laboratory tests and direct sequencing of PROC and SERPINC1 were conducted for the patient and his family members. Coagulation tests revealed that the patient presented type I antithrombin deficiency combined with decreased protein C activity resulting from a small insertion mutation c.848_849insGATGT in SERPINC1 and a short deletion variant c.572_574delAGA in PROC. This combination of the two mutations was absent in 400 healthy subjects each from southern and northern China. Then, we summarized all the mutations of the SERPINC1 and PROC gene reported in the Chinese Han population. This study demonstrates that the combination of antithrombin deficiency and decreased protein C activity can result in severe VTE and that the coexistence of different genetic factors may increase the risk of VTE.
Antithrombin III ; genetics ; Antithrombin III Deficiency ; etiology ; genetics ; China ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Pedigree ; Protein C ; genetics ; metabolism ; Venous Thromboembolism ; complications ; genetics ; Young Adult

OBJECTIVETo study the molecular mechanism of antithrombin (AT) gene C2759T (Leu99Phe) mutation causing AT deficiency.

METHODSA mutated AT cDNA expression plasmid ATM2759 was constructed by mega-primer method. ATM2759 and wild type AT cDNA expression plasmid ATN were transfected into COS7 cells or CHO cells by using Superfect reagent respectively for in vitro expression study and immunofluorescence assay.

RESULTSThe antigen levels of AT (AT:Ag) in the cell lysate of ATM2759 transfected COS7 cells and the cell culture supernatant were 174.97% and 35.63% of that of ATN transfected COS7 cells respectively, whereas the AT activity in the cell culture supernatant was 47.73% of the control's. Immunofluorescence analysis showed that the fluorescence intensity was significantly higher in ATM2759 transfected CHO cells than in those transfected with ATN.

CONCLUSIONSLeu99Phe substitution may not affect the binding capacity of AT with heparin. Secretion defect and intracellular accumulation of the mutated AT protein might be the mechanisms of this mutation causing AT deficiency.

Animals ; Antithrombin III ; genetics ; metabolism ; Antithrombin III Deficiency ; genetics ; CHO Cells ; COS Cells ; Cercopithecus aethiops ; Cricetinae ; Cricetulus ; Fluorescent Antibody Technique ; Mutation ; Plasmids ; genetics ; Transfection

Adolescent ; Adult ; Antithrombin III Deficiency ; genetics ; Antithrombins ; Female ; Humans ; Male ; Mutation ; Pedigree ; Phenotype

Objective: To analyze the clinical manifestations and molecular pathogenesis of 18 patients with inherited protein S (PS) deficiency. Methods: Eighteen patients with inherited PS deficiency who were admitted to the Institute of Hematology & Blood Diseases Hospital from June 2016 to February 2019 were analyzed: activity of protein C (PC) and antithrombin (AT) , PS activity were measured for phenotype diagnosis; high throughput sequencing (HTS) was used for screening of coagulation disease-related genes; Sanger sequencing was used to confirm candidate variants; Swiss-model was used for three-dimensional structure analysis. Results: The PS:C of 18 patients ranged from 12.5 to 48.2 U/dL. Among them, 16 cases developed deep vein thrombosis, including 2 cases each with mesenteric vein thrombosis and cerebral infarction, and 1 case each with pulmonary embolism and deep vein thrombosis during pregnancy. A total of 16 PROS1 gene mutations were detected, and 5 nonsense mutations (c.134_162del/p.Leu45*, c.847G>T/p.Glu283*, c.995_996delAT/p.Tyr332*, c.1359G> A/p.Trp453*, c.1474C>T/p.Gln492*) , 2 frameshift mutations (c.1460delG/p.Gla487Valfs*9 and c.1747_1750delAATC/p.Asn583Wfs*9) and 1 large fragment deletion (exon9 deletion) were reported for the first time. In addition, the PS:C of the deep vein thrombosis during pregnancy case was 55.2 U/dL carrying PROC gene c.565C>T/p.Arg189Trp mutation. Conclusion: The newly discovered gene mutations enriched the PROS1 gene mutation spectrum which associated with inherited PS deficiency.
Antithrombin III/genetics* ; Female ; Genetic Testing ; Humans ; Mutation ; Pregnancy ; Protein C/genetics* ; Protein S/genetics* ; Protein S Deficiency/genetics*

OBJECTIVETo investigate the antithrombin (AT) activity (AT: A) and AT antigen (AT: Ag) level in a Chinese family with type I antithrombin (AT) deficiency, and to explore the molecular mechanism of AT deficiency.

METHODSImmuno-nephelometry and chromogenic assay were used to detect the plasma level of AT: A and AT: Ag, respectively. Genomic DNA was isolated from the peripheral blood, and all the seven exons and exon-intron boundaries of AT gene were amplified by PCR and direct sequencing.

RESULTSThe plasma levels of AT: A and AT: Ag of the proband were 45% and 97 mg/L, respectively, which led to a type I AT deficiency. A heterozygous T to A mutation was found at nucleotide 9833 in exon 5 resulting in a Tyr363Stop nonsense mutation. The sequencing results from the pedigree indicated that four other members also had this mutation.

CONCLUSIONThis heterozygous nonsense mutation of T9833A in exon 5 resulting in venous thrombosis is a novel genetic defect of hereditary AT deficiency, which has not been described before.

Antithrombin III Deficiency ; genetics ; Antithrombins ; genetics ; Blood Coagulation Tests ; Female ; Humans ; Male ; Mutation ; Pedigree ; Polymerase Chain Reaction ; Sequence Analysis, DNA

OBJECTIVETo explore the phenotype, genotype and molecular mechanism for two pedigrees affected with hereditary antithrombin (AT) deficiency.

METHODSClinical diagnosis was validated by assaying of coagulation parameters including prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, antithrombin activity (AT:A) and specific antigen (AT:Ag), protein C activity, as well as protein S activity. To detect potential mutations in the probands, all exons, exon-intron boundaries and the 3', 5' untranslated regions were amplified by PCR and subjected to direct sequencing. Suspected mutation was confirmed by reverse sequencing and silver staining. The effect of mutations on the AT protein was analyzed with bioinformatics software.

RESULTSThe AT:Ag of pedigree 1 was normal, but its AT:A has reduced to 30%. A heterozygous c.235C>T mutation in exon 2 causing p.Arg47Cys, in addition with two single nucleotide polymorphisms (c.981G>A, c.1011G>A) in exon 5 were identified in the patient. His four children, except for the elder daughter, were heterozygous for the mutations. The plasma levels of AT:A and AT:Ag in proband 2 have decreased to 39% and 103 mg/L, respectively. A heterozygous deletion (g.5890-5892delCTT) leading to loss of p.Phe121 was also detected in his father. Bioinformatic analysis suggested that the missense mutation Arg47Cys can affect the functions of AT protein. Meanwhile, lacking of Phe121 will result in loss of hydrogen bonds with Ala124, Lys125 and the cation π interactions with Lys125, Arg47, which may jepordize the stability of the protein.

CONCLUSIONThe proband 1 had type II AT deficiency, while proband 2 had type I AT deficiency. The p.Arg47Cys and g.5890-5892delCTT mutations of the AT gene are significantly correlated with the levels of AT in the two probands, respectively.

Adult ; Aged, 80 and over ; Antithrombin III ; genetics ; metabolism ; Antithrombin III Deficiency ; enzymology ; genetics ; physiopathology ; Exons ; Female ; Genetic Testing ; Genotype ; Humans ; Male ; Mutation ; Partial Thromboplastin Time ; Pedigree ; Phenotype ; Protein C ; genetics ; metabolism ; Protein S ; genetics ; metabolism