Objective of this study was to identify gene mutation involved in a patient with type 2A von Willebrand disease (vWD). The bleeding time, vWF:Ag, FVIII:C, RIPA and multimeric assay were used for phenotypic diagnosis. All of the 52 exons and the exon-intron boundaries of vWF gene were amplified by polymerase chain reaction (PCR) and direct sequencing was carried out. The results indicated that the levels of vWF:Ag, FVIII:C and RIPA decreased in this patient, the vWF multimer with high and intermediate molecular weight was absent in plasma. The sequencing of genomic DNA revealed a C4738G (L1580V) missense mutation in the vWF gene from the patient. In conclusion, the C4738G (L1580V) missense mutation effecting the form of vWF multimer was responsible to molecular mechanism in this patient with vWD.
Adult ; Humans ; Male ; Mutation, Missense ; von Willebrand Disease, Type 2 ; genetics ; von Willebrand Factor ; analysis ; genetics

A 10-year-old male patient affected by type 2 von Willebrand disease (vWD) and his family members were investigated by hemostatic and molecular genetic studies. The propositus, who experienced frequent bleeding episodes, was characterized by a normal level of von Willebrand factor (vWF) antigen (54%), reduced vWF ristocetin cofactor activity (5%), decreased factor VIII clotting activity (25%) and absent high molecular weight multimers in the plasma. An exon 28 fragment coding for the A1 and A2 domains was amplified by polymerase chain reaction and sequenced. We found a heterozygous mutation (G4022A), producing an additional PstI restriction site, which resulted in the substitution of Arg578Gln. Family studies, including the parents and a brother, were negative for this mutation and vWF abnormalities were not observed. We confirmed that G to A mutation in the region of the platelet glycoprotein Ib binding domain of vWF causes the qualitative type 2 defect in von Willebrand disease.
Alanine/genetics* ; Case Report ; Child ; Glycine/genetics* ; Human ; Male ; Point Mutation* ; von Willebrand Disease/genetics* ; von Willebrand Factor/genetics*

OBJECTIVETo analyze the phenotype and genotype of two Chinese pedigrees with von Willebrand diseases, and to investigate the molecular pathogenesis.

METHODSBleeding time (BT), activated partial thromboplastin time (APTT), ristocetin-induced platelet aggregation (RIPA), von Willebrand factor-ristocetin cofactor (vWF:Rco), von Willebrand factor antigen (vWF:Ag), von Willebrand factor activity (vWF:A), von Willebrand factor collagen binding assay (vWF:CB) and multimer analysis were used for phenotype diagnosis. DNA was extracted. All of the 52 exons and exon-intron bounda ries of the VWF gene were amplified with polymerase chain reaction(PCR) and analyzed by direct sequencing.

RESULTSAPTT and BT were prolonged. Plasma RIPA, vWF:Rco, vWF:Ag, vWF:A and vWF:CB was significantly decreased. No VWF multimer can be found by plasma VWF multimer analysis. Homozygous insertional mutation g.82888_82889insCATG in exon 17 was found in proband A. Compound heterozygous mutations g.94865 G to A (Trp856stop) in exon 20 and g.110698_110699delinsG in exon 28 were found in proband B.

CONCLUSIONHomozygous insertional mutation g.82888_82889insCATG and compound heterozygous mutations g.94865G to A(Trp856X) and g.110698_110699delinsG probably have respectively induced type 3 von Willebrand diseases in the two probands.

Adolescent ; Female ; Genotype ; Humans ; Male ; Mutation ; Pedigree ; Phenotype ; von Willebrand Disease, Type 3 ; genetics ; von Willebrand Factor ; genetics

BACKGROUND: von Willebrand disease (VWD), characterized by quantitative or qualitative defects of von Willebrand factor (VWF), is the most common inheritable bleeding disorder. Data regarding the genetic background of VWD in Korean patients is limited. To our knowledge, this is the first comprehensive molecular genetic investigation of Korean patients with VWD. METHODS: Twenty-two unrelated patients with VWD were recruited from August 2014 to December 2017 (age range 28 months–64 years; male:female ratio 1.2:1). Fifteen patients had type 1, six had type 2, and one had type 3 VWD. Blood samples were collected for coagulation analyses and molecular genetic analyses from each patient. Direct sequencing of all exons, flanking intronic sequences, and the promoter of VWF was performed. In patients without sequence variants, multiplex ligation-dependent probe amplification (MLPA) was performed to detect dosage variants. We adapted the American College of Medical Genetics and Genomics guidelines for variant interpretation and considered variants of uncertain significance, likely pathogenic variants, and pathogenic variants as putative disease-causing variants. RESULTS: VWF variants were identified in 15 patients (68%): 14 patients with a single heterozygous variant and one patient with two heterozygous variants. The variants consisted of 13 missense variants, one small insertion, and one splicing variant. Four variants were novel: p.S764Efs*16, p.C889R, p.C1130Y, and p.W2193C. MLPA analysis in seven patients without reportable variants revealed no dosage variants. CONCLUSIONS: This study revealed the spectrum of VWF variants, including novel ones, and limited diagnostic utility of MLPA analyses in Korean patients with VWD.
Exons ; Genetic Background ; Genetics, Medical ; Genomics ; Hemorrhage ; Humans ; Introns ; Korea ; Molecular Biology ; Multiplex Polymerase Chain Reaction ; von Willebrand Disease, Type 3 ; von Willebrand Diseases ; von Willebrand Factor

OBJECTIVETo investigate the susceptibility of von Willebrand factor (VWF) type 2A mutant A1500E to proteolysis by metalloprotease ADAMTS13 and to provide the direct supports for the pathogenesis of VWF mutation A1500E responsible for von Willebrand disease (VWD) type 2A.

METHODSRecombinant wild-type VWF (WT-VWF) and A1500E mutant VWF transiently expressed on transfected HeLa cell lines. Expression media were collected and concentrated, then cleaved directly by recombinant ADAMTS13 (rADAMTS13). Compared with WT-VWF, the susceptibility of A1500E mutant VWF to proteolysis by ADAMTS13 was analyzed using SDS-agarose gel VWF multimers analysis.

RESULTSIn vitro the expression of VWF:Ag in the supernatants of WT-VWF and A1500E mutant VWF were 1.10 U/ml and 0.78 U/ml, respectively, while VWF:Ag in cells lysates of A1500E mutant VWF was 90.6% of that of WT-VWF. The SDS-agarose gel VWF multimers analysis showed that there were no differences between WT-VWF and A1500E mutant VWF. The A1500E mutant VWF could be efficiently cleaved by ADAMTS13 under static condition without denaturants such as urea and guanidine HCl. VWF multimeric analysis showed that high and intermediate molecular weight multimers dramatically decreased while low molecular weight multimers obviously increased. Conversely, WT-VWF could not be cleaved by ADAMTS13 under the same condition.

CONCLUSIONThe A1500E mutation resulted in VWF more susceptible to ADAMTS13-dependent proteolysis, which belonged to VWD type 2A group 2 mutation.

ADAM Proteins ; genetics ; metabolism ; ADAMTS13 Protein ; Genotype ; HeLa Cells ; Humans ; Hydrolysis ; Mutation ; Recombinant Proteins ; genetics ; metabolism ; von Willebrand Disease, Type 2 ; genetics ; metabolism ; von Willebrand Factor ; genetics

Type 2N von Willebrand disease (vWD) can be confused with hemophilia A due to decreased factor VIII levels and a bleeding tendency, and differential diagnosis is of importance for providing the optimal treatment and genetic counseling. For the accurate diagnosis of type 2N vWD, von Willebrand Factor (vWF) function tests, multimer assay and gene mutation analysis are needed. The patient was a 38-yr-old Nepalese woman with a history of bleeding manifestations from childhood, such as hemarthrosis, intramuscular hematoma, and menorrhagia. Family history revealed that her mother and elder brothers also had bleeding manifestations from childhood. When she had a laparotomy in 1991, she was diagnosed as hemophilia A with factor VIII level of 3.6% and was transfused with whole blood, factor VIII and cryoprecipitates. In June 2007, she was admitted to our hospital for further evaluation of bleeding tendency. Blood tests revealed normal CBC; bleeding time, 2 min; PT, 14.9 sec (11-14 sec); aPTT, 51.2 sec (24-38 sec); and factor VIII, 4.9% (50-150%). The prolonged aPTT was corrected by 1:1 mixing test to the levels of 106% and 84%, respectively, before and after 2 hr-incubation at 37degrees C. No abnormalities were found in the vWF antigen level (71.3%), ristocetin cofactor assay (130.4%), and multimer assay. Direct DNA sequencing of the VWF gene revealed homozygous missense mutation located in exon 19, c.2446C>T (p.Arg816Trp), confirming the diagnosis of type 2N vWD.
Adult ; Amino Acid Substitution ; Asian Continental Ancestry Group/genetics ; Base Sequence ; Female ; Genotype ; Homozygote ; Humans ; Nepal ; von Willebrand Disease/blood/*diagnosis/genetics ; von Willebrand Factor/analysis/*genetics

OBJECTIVETo provide genetic and prenatal analysis for a pedigree affected with type 3 von Willebrand disease.

METHODSNext generation sequencing and Sanger sequencing of the VWF gene were carried out for the pedigree. Suscepted pathogenic mutation was verified among other members of the pedigree and 100 healthy controls. Prenatal diagnosis was performed on amniotic cells derived from the fetus.

RESULTSA homozygous mutation c.7287+1G>A of the VWF gene was detected in the patient, which was predicted by bioinformatic analysis as a pathological splice site mutation. The parents and sister of the patient have all carried the same mutation. The mutation was not detected among the 100 healthy controls. Prenatal diagnosis confirmed that the fetus did not inherit the same mutation.

CONCLUSIONA novel mutation of the VWF gene was discovered, which correlated with the phenotype of the patient. Based on the discovery, prenatal diagnosis was provided for a fetus during subsequent pregnancy.

Child, Preschool ; Computational Biology ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Mutation ; Pedigree ; Prenatal Diagnosis ; von Willebrand Disease, Type 3 ; diagnosis ; genetics ; von Willebrand Factor ; genetics

BACKGROUND: We intended to find the mutations of von Willebrand factor (VWF) gene as the most important contributing factor of von Willebrand disease (VWD) in Korean patients. METHODS: In 40 known vWD patients mutations of vWF gene were sought by direct sequencing of PCR products targeting exons 18, 19, 20, 26, 28 and 52 frequently implicated as the locations of mutation. For factors other than VWF gene contributing to VWD phenotype, we tested ABO blood group and measured ADAMTS13 activity in VWD patients. RESULTS: Twenty-seven cases (67.5%) were type 1 vWD, 3 cases (7.5%) type 3, and 5 cases (12.5%) type 2A. Three cases were type 2A or 2B (7.5%) and 2 cases were suspected to be type 2N (5.0%). Among them six candidate missense mutations were found: V1279I, R1306W, R1308C, and V1316M were previously reported in type 2B and type 1 vWD, and C858W and T1477I were novel findings. All patients were heterozygotes. Blood group O was overly represented in VWD patients, while ADAMTS13 activity of the patients was not significantly different from that of normal control. CONCLUSIONS: Mutation of VWF gene detected by genetic studies can significantly improve the diagnostic accuracy, especially in subtype assignment of VWD. Two novel mutations, C858W and T1477I associated with VWD were found and expected to contribute to the elucidation of its pathophysiology.
ABO Blood-Group System ; ADAM Proteins/analysis ; Heterozygote ; Humans ; Korea ; *Mutation, Missense ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Sequence Analysis, DNA ; von Willebrand Disease/classification/diagnosis/*genetics ; von Willebrand Factor/analysis/*genetics

This study was purposed to investigate the vWF gene A1381T polymorphism in patients with coronary heart disease (CHD). A case-control study was designed, including 104 continuously hospitalized patients with CHD, aging from 40 to 75 years (average 59) and 96 persons underwent physical examination in outpatient department as controls, aging from 39 to 70 years (average 56). The plasma vWF: Ag level of CHD patients and control persons was detected by ILISA. vWF gene A1381T polymorphism was analyzed by the polymerase chain reaction-restriction fragment length polymorphism and sequencing when it is necessary. The data were grouped by gender, blood group and/or genotype in CHD group and control groups. The difference of plasma vWF level between male and female was analyzed by independent sample t test; one way ANOVA was used to analyze the difference of vWF level between different blood group genotypes, while the factorial design ANOVA was used to test the difference of vWF level in plasma between A1381T genotype and/or ABO blood groups. χ(2) Crosstabs were used to test the CHD susceptibility. The results showed that the frequencies of GG genotype (wild type) of vWF gene A1381T polymorphism were 62.5% in CHD group and 67.7% in control group, and the frequencies of AG genotype (heterozygous variant) were 37.5% in CHD group and 32.3% in control group. χ(2) Crosstabs showed no significant correlation between vWF gene A1381T polymorphism (AG) and CHD (OR = 1.258, 95% CI = 0.702 - 2.255, χ(2) = 0.595, p = 0.440). The plasma vWF level in CHD group was statistically very higher than that in control group (p < 0.001), even though the relationship of vWF A1381T polymorphism (rs216311) and susceptibility of CHD in CHD group was not found. The plasma vWF level of AG or GG genotype was higher in CHD group than in control group (p < 0.001). The plasma vWF level of AG genotype was higher than that of GG in CHD group (p < 0.05), but not in control group. The plasma vWF of O blood group was lower than that of A, B and AB blood groups (p < 0.05), while among A, B, AB blood groups, the vWF level was not different (p > 0.05). Among O, A, B, AB blood groups in CHD group, vWF level was not different (p > 0.05). Although the two-way analysis of variance ANOVA showed no interaction of A1381T genotype and ABO blood groups on plasma vWF level, the plasma vWF level in AG mutant of vWF A1381T gene polymorphism with O blood group was higher than that of GG mutant (p = 0.023) in CHD group, not different in other blood groups. It is concluded that there is no association between vWF gene A1381T polymorphism and CHD susceptibility. The plasma vWF level in CHD group interrelated with ABO blood group and A1381T polymorphism, in which the plasma vWF level in AG genotype increase mostly. Plasma vWF level in vWF gene A1381T polymorphism with AG mutant was significantly much higher than GG mutant in CHD. This change may be beneficial to further study the effect of A1381T polymorphism on vWF gene expression and activity.
ABO Blood-Group System ; Adult ; Aged ; Case-Control Studies ; Coronary Disease ; genetics ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Genetic ; von Willebrand Factor ; genetics

OBJECTIVETo assess the association of rs216293 T/G and rs1063857 T/C polymorphisms of von Willebrand factor (vWF) gene with the morbidity of coronary artery disease (CAD) and the number of involved vessels among an ethnic Han Chinese population from Zhejiang province.

METHODSA case-control study was conducted. For 246 patients and 156 unaffected controls, the frequencies of genotypes and alleles of the rs216293T/G and rs1063857T/C polymorphisms were determined, and their association with CAD and the numbers of involved vessels were assessed.

RESULTSThe frequencies of G allele of rs216293 and C allele of rs1063857 were higher in the CAD patients compared with those of the controls (30.3% vs.23.7%, chi-square=4.107, P=0.043; 7.7% vs. 4.2%, chi-square=4.066, P=0.044). The G allele of the rs216293 polymorphism and C allele of the rs1063857 polymorphism were both higher in the CAD patients compared with the controls (53.7% vs.41.0%, chi-square=6.098, P=0.014; 15.4% vs. 8.3%, chi-square=4.361, P=0.037). After adjusting the influence factors by logistic regression analysis, the G allele carriers of rs216293 and the C allele carriers of rs1063857 showed an increased risk for CAD (OR=1.625, 95%CI: 1.060-2.492, P=0.026; OR=2.305, 95% CI: 1.142-4.654, P=0.040). No significant difference was detected in the frequency of both rs216293 and rs1063857 among patients with single or multiple vessels (P>0.05).

CONCLUSIONThe rs216293T/G and rs1063857T/C polymorphisms of the vWF gene are both associated with the risk for CAD among the selected population. The G allele of the rs216293 polymorphism and C allele of the rs1063857 polymorphism may be the genetic determinants for CAD.

Adult ; Aged ; Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; China ; epidemiology ; ethnology ; Coronary Artery Disease ; epidemiology ; ethnology ; genetics ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; ethnology ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Risk Factors ; von Willebrand Factor ; genetics