Proband: FA_II:1, male uknown age

FamilyDetails: heterozygous unaffected parents, parents were first cousins, VWF:Ag on low end of reference range

Labs: prolonged bleeding time (15min), reduced VWF:Ag (0.06 IU/mL), FVIII:Ag (0.18 IU/mL), FVIII:C (0.20 IU/mL), and VWF:RiCoF (0.06 IU/mL), absent multimers

Genotype: p.Arg273Trp reported as c.1067C>T (MANE transcript is 817C>T)

CAID: CA228829

Proband: FB_II:3, male age unknown

Family details: parents are unaffected heterozygotes, VWF:Ag on the low end of reference range

Labs: prolonged bleeding time (15min), reduced VWF:Ag (0.09 IU/mL), FVIII:Ag (0.33 IU/mL), FVIII:C (0.21 IU/mL), and VWF:RiCoF (0.04 IU/mL), absent multimers

Genotype: p.Arg273Trp reported as c.1067C>T (MANE transcript is 817C>T)

CAID: CA228829

Proband: FC_II:6, male age unknown

FamilyDetails: parents are unaffected hets, first cousins, fathers VWF:Ag at very low end of reference

Labs: prolonged bleeding time (>20min), reduced VWF:Ag (less than 0.01 IU/mL), FVIII:Ag (0.06 IU/mL), FVIII:C (0.09 IU/mL), and VWF:RiCoF (less than 0.01 IU/mL), absent multimers

Genotype: p.Arg273Trp reported as c.1067C>T (MANE transcript is 817C>T)

CAID: CA228829

PMID: 35747851

Notes: some type 1C assertions, including p.Cys1190Arg which is in the same codon as p.Cys1190Tyr which seems solidly 2A

PMID: 16409463

Notes: several variants, currently curating c.823T>C (p.Cys275Arg) and family 11 proband is compound het with p.Pro1337Leu. Nucleotide position are not provided and the family is asserted as type B but no GPIb, RIPA or VWF platelet binding assay data are reported.

PMID: 30036281<br /> Gene: VWF<br /> Disease: von Willebrand disease<br /> MonDO: 0015631<br /> HGNCID:

Proband: Mazurier_II2

AgeAtReport: 20yo female

HPO: HP:0000421, HP:0002248, hematoma but did not specify spontaneous and/or frequent

Labs: 4 measurements taken for the same proband so values are a range: FVIII:C 4-10 IU/dL, VWF:Ag 30-53 IU/dL, FVIII:Ag 4-8 IU/dL, VWF:FVIIIB absent

Variant: C1060R - NM_000552.5:c.3178T>C (maternal)

Variant: Y357X - NM_000552.5:c.1071C>A (paternal)

CAID: CA114176

CAID: CA114174

PMID: 32864553

Notes: case cohort with good genotyping of variants in supp. methods. The only omission is a clear/explicit statement or reporting of excessive bleeding phenotype with the cases and disclosing familial relationships

PMID: 19773258

Notes: c.2546+3G>C variant with confirmed splicing impact, exon 19 skipping and premature stop codon in exon 20 leading to NMD. Lab values are borderline normal and not inclusive of values needed for type 2N

CAID: CA2013880906

PatientDetails: more detailed proband and proband father lab values are in the supplementary data

Case: Case 2, male, hispanic, symptom onset at birth

DiseaseAssertion: Platelet-type VWD (PT-VWD)

FamilyInfo: Parents were tested for platelet antigen 5a (HPA5a): mother was negative and father was positive, parents had normal VWD panels including VWF multimer and RIPA test

ParentalGenotype(s): NA

CasePresentingHPOs: HP:0004846, HP:0000978, HP:0001873, HP:0012541, HP:0030132

(Prolonged bleeding after surgery, easy bruising, thrombocytopenia, Cephalohematoma, Absence of large von Willebrand factor multimers)

CaseHPOFreeText: peripheral blood smear showed platelet clumping and large granular platelets, Platelet (×109/L) = 61, Factor VIII (IU/mL) = 0.94, VWF:Ag (IU/mL) = 0.88, VWF:RCo (IU/mL) = 0.34, VWF:CB (IU/mL) = ND, RCo/Ag ratio = 0.39, CB/Ag ratio = NA, VWF: HMW Multimers = absent

CaseNOTHPOs: NA

CaseNOTHPOFreeText: umbilical cord bleeding, bleeding after heel stick

CasePreviousTesting: no mutations in exon 28 of VWF gene

GenotypingMethod: NA

PreviouslyPublished: NA

Gene: GP1BA

Variant: c.763A>G (p.Met255Val)

HGVS: NM_000173.7(GP1BA):c.763A>G (p.Met255Val)

ClinVarID: 4155; https://www.ncbi.nlm.nih.gov/clinvar/variation/4155/

CAID:

gnomAD: absent

Case: Case 3, female

DiseaseAssertion: Platelet-type VWD (PT-VWD)

FamilyInfo: NA

ParentalGenotype(s): NA

CasePresentingHPOs: HP:0000978, HP:0000421, HP:0000132, HP:0004846, HP:0001873, HP:0030129, HP:0030132

(easy bruising, epistaxis, Menorrhagia, Prolonged bleeding after surgery, thrombocytopenia, Impaired ristocetin cofactor assay activity, Absence of large von Willebrand factor multimers)

CaseHPOFreeText: pregnancy complicated by progressive thrombocytopenia; Platelet (×109/L) = 135, Factor VIII (IU/mL) = 0.78, VWF:Ag (IU/mL) = 0.69, VWF:RCo (IU/mL) = 0.22, VWF:CB (IU/mL) = ND, RCo/Ag ratio = 0.32, CB/Ag ratio = ND, VWF: HMW Multimers = absent

CaseNOTHPOs: NA

CaseNOTHPOFreeText: NA

CasePreviousTesting: NA

GenotypingMethod: NA

PreviouslyPublished: NA

Gene: GP1BA

Variant: c.746G>T (p.Gly249Val)

HGVS: NM_000173.7(GP1BA):c.746G>T (p.Gly249Val)

ClinVarID: 4153; https://www.ncbi.nlm.nih.gov/clinvar/variation/4153/

CAID:

gnomAD: absent

Case: Case 1, male, 13yo at assessment, symptom onset at 45 days old

DiseaseAssertion: Platelet-type VWD (PT-VWD)

FamilyInfo: 1 symptomatic sister (menorrhagia, hemorrhagic follicular cyst); 1 asymptomatic sister; 3 brothers: twin died at 45days old due to leukemia, 1 symptomatic with daily epistaxis, 1 asymptomatic; father had bleeding symptoms; mom had severe bleeding with c-section requiring hysterectomy

ParentalGenotype(s): NA

CasePresentingHPOs: HP:0001973, HP:0001892, HP:0000421, HP:0000979, HP:0001873, HP:0002090, HP:0000023, HP:0030132, HP:0011871

(Autoimmune thrombocytopenia, abnormal bleeding, epistaxis, purpura, thrombocytopenia, pneumonia, inguinal hernia, Absence of large von Willebrand factor multimers, impaired RIPA)

CaseHPOFreeText: bleeding treated with intravenous gamma-globulin (IVIg) and corticosteroids, laparoscopic splenectomy complicated by massive intraperitoneal bleeding, multiple bone marrow aspirations performed; born via c-section of twin pregnancy due to placenta previa; mepacrine uptake assay by flow cytometry was normal, Blood smear showed very large platelets with clear signs of activation and pseudopods; Platelet (×109/L) = 95, Factor VIII (IU/mL) = 1.00, VWF:Ag (IU/mL) = 1.29, VWF:RCo (IU/mL) = 0.28, VWF:CB (IU/mL) = 0.70, RCo/Ag ratio = 0.22, CB/Ag ratio = 0.54, VWF: HMW Multimers = partial loss

CaseNOTHPOs: NA

CaseNOTHPOFreeText: NA

CasePreviousTesting: NA

GenotypingMethod: NA

PreviouslyPublished: NA

Gene: GP1BA

Variant: c.763A>G (p.Met255Val)

HGVS: NM_000173.7(GP1BA):c.763A>G (p.Met255Val)

ClinVarID: 4155; https://www.ncbi.nlm.nih.gov/clinvar/variation/4155/

CAID:

gnomAD: absent

Case: Case 4, female, 5yo at onset, 20yo at report

DiseaseAssertion: Platelet-type VWD (PT-VWD)

FamilyInfo: Fhx of VWD; father diagnosed with type 2B VWD

ParentalGenotype(s): NA

CasePresentingHPOs: HP:0000978, HP:0000421, HP:0000132, HP:0001873, HP:0004846

(easy bruising, epistaxis, menorrhagia, thrombocytopenia, Prolonged bleeding after surgery)

CaseHPOFreeText: pregnancy complicated by thrombocytopenia, Platelet aggregation studies were normal to ADP, epinephrine, collagen, and arachidonic; Platelet (×109/L) = 156, Factor VIII (IU/mL) = ND, VWF:Ag (IU/mL) = 0.57, VWF:RCo (IU/mL) = 0.86, VWF:CB (IU/mL) = ND, RCo/Ag ratio = 1.15, CB/Ag ratio = ND, VWF: HMW Multimers = normal

CaseNOTHPOs: NA

CaseNOTHPOFreeText: NA

CasePreviousTesting: no mutations in exon 28 of the VWF gene

GenotypingMethod: NA

PreviouslyPublished: NA

Gene: GP1BA

Variant: c.746G>T (p.Gly249Val)

HGVS: NM_000173.7(GP1BA):c.746G>T (p.Gly249Val)

ClinVarID: 4153; https://www.ncbi.nlm.nih.gov/clinvar/variation/4153/

CAID:

gnomAD: absent

Probands: Pt36, 76, 77 same family

Labs: for Pt.36, VWF:Ag 17 IU/dL, VWF:RCo/VWF:Ag 0.37, VWF:GPIb/VWF:Ag 0.38, and normal multimers per data in table S1

CAID: CA383506019

Proband: F4_AM, 27yo (at report) female

Phenotypes: HP:0030134, HP:0003010, HP:0030129

Family: Both parents carry the variant. All het carriers were classified type 1

Labs: FVIII 0.02 IU/mL, VWF 0.03 IU/mL (below detection threshold)

Variant: NM_000552.5:c.4975C>T

CAID: CA114141

PMID: 34532631

Notes: Homozygous instance of an otherwise type 2 variant, Cys1190Arg

Variant: c.823T>C p.Cys275Arg - used family membevr III-2 as proband for PP4

PMID: 11154147

Notes: Tyr1321Asp reported as Tyr558Asp and c.4211T>G

CAID: CA383506021

Case: 24-year-old Caucasian woman with a rare variety of type 2M VWD

DiseaseAssertion: 2M VWD

FamilyInfo: family history was negative for easy bruisability, bleeding, or clotting disorder but maternal grandmother had lung cancer.

CaseNOTHPOFreeText: Von Willebrand factor antigen 45% on 9/12/17 and 37% on 9/19/17 with the ratio of VWF activity to the antigen is less than 0.7

ParentalGenotype(s):Unknown

CasePresentingHPOs: HP:0003010 (Prolonged bleeding time), HP:0000978 (Bruising susceptibility).

**CaseHPOFreeText: ** loss of weight over the last six months, The complete blood count, comprehensive metabolic panel, factor VIII, prothrombin time and partial thromboplastin time, D-Dimer, and antithrombin activity were normal. Her von Willebrand factor activity was much lower compared to the antigen.

CasePreviousTesting: None

GenotypingMethod: Patient have not been genotyped

PreviouslyPublished: N/A

Variant: N/A

ClinVarID: N/A

gnomAD: N/A

**Gene: ** VWF Inheritance mode autosomal dominant variety with normal, high molecular weight multimers

Disease: Von-willebrand Disease (Type 2A)

Patient: 50 yo female

Variant: VWF NM_000552.5 c:4232_4249del p.(Val411_Ile416del), Exon 28, heterozygous variant

According to this paper, ACMG-AMP guidelines for interpreting this variant resulted in classification of likely pathogenic

Phenotypes: increased bruising, fatigue, recurrent sinusitis, menorrhagia, neutropenia, anaemia. Reduction in high-molecular-weight multimers

Family: segregation analysis showed two affected family members had the variant and two unaffected family members did not have variant.

Note: Patient also has diagnosed Acute Myeloid Leukaemia (AML) NM_000546.6(TP53):c704A>G p.(Asn235Ser), listed as VUS and found by NGS

Disease: Von-willebrand Disorder (2N)

Patient: 32 yo, male

Variant: VWF NM_000552.5 c:2527C>T, p.(Arg760Cys), exon 17, noted to be dominant effect

Note: Proband also has an Arg91Gln mutation in exon 20 of VWF too.

Phenotypes: Mild bleeding history, epistaxis, bleeding gums, bleeding after tooth extraction. 11 years old had severe hemorrhage following tonsillectomy. Previous diagnosis of hemophilia A.

Family: father has history of epistaxis but never eamined prior to study. Father has the Arg760Cys mutation at heterozygous level. Mother is asymptomatic and classified as hemophilia A carrier following hemophilia A diagnosis in son. Mother also has the Arg91Gln mutation in exon 20 at heterozygous level.

Molecular Phenotypes: mild decrease in plasma FVIII and VWF levels, normal platelet VWF content, decreased FVIII binding capacity of VWF. Causes retention of pro-VWF(suggest defects in the maturation process of VWF). Abnormal VWF and platelet GPIb interaction(documented by impaired or absent RIPA and decreased VWF:RCo).

CLEC4M(rs753084254):c.C>T, noted as synonymous protein effect and VarSome classifies it as a VUS.

CLEC4M(rs113080783):c.A>G, noted as missense protein effect and VarSome classifies it as a VUS.

CLEC4M(rs62623420):c.A>G,noted as Splice acceptor protein effect and VarSome classifies it as a VUS.

CLEC4M(rs868878):c.G>A, noted as synonymous protein effect and VarSome classifies it as Benign.

CLEC4M(rs2277998):c.G>A, noted as missense protein effect and VarSome classifies it as Benign

TC2N(rs756737332):c.C>T, noted as missense protein effect and VarSome classifies it as a VUS.

TC2N(rs144110131):c.T>G, noted as missense protein effect and VarSome classifies it as a VUS.

TC2N(rs2402073):c.G>T, noted as missense protein effect and VarSome classifies it as Benign

TC2N(rs2402073):c.G>A,noted as missense protein effect and VarSome classifies it as Likely Benign

STX2(rs145834567):c.T>C, noted as missense protein effect and Varsome classifies it as a VUS.

STX2(rs137928907):c.A>C, noted as missense protein effect and Varsome classifies it as a VUS.

STX2(rs17564):c.G>C, noted as missense protein effect and Varsome classifies it as Benign.

SCARA5(rs17058374):c.C>T, noted as missense protein effect and VarSome classifies it as Likely Benign.

SCARA5(rs61737292):c.G>A, noted as missense protein effect and VarSome classifies it as Benign.

SCARA5(rs148420420):c.C>T, noted as synonymous protein effect and VarSome classifies it as a VUS.

SCARA5(rs61737296):c.G>A, noted as synonymous protein effect and VarSome classifies it as Likely Benign.

SCARA5(rs118119884):c.G>A, noted as missense protein effect and VarSome classifies it as Benign.

SCARA5(rs6983356):c.G>A, noted as synonymous protein effect and VarSome classifies it as Benign.

SCARA5(rs17058207):c.C>G, noted as missense protein effect and VarSome classifies it as Benign.

SCARA5(rs61737291):c.G>A, noted as synonymous protein effect and VarSome classifies it as Benign.

SCARA5(rs4732610):c.G>A, noted as synonymous protein effect and VarSome classifies it as Benign.

SCARA5(rs10103504):c.T>C, noted as synonymous protein effect and VarSome classifies it as Benign.

STAB2(rs760013563):c.C>T, noted as synonymous protein effect and VarSome classifies it as a VUS

STAB2(rs377067548):c.C>G, noted as synonymous protein effect and VarSome classifies it as a VUS

STAB2(rs377011398):c.G>A, noted as missense protein effect and VarSome classifies it as a VUS

STAB2(12:104067708):c.T>C, noted as missense protein effect and VarSome classifies it as a VUS

STAB2(rs766516074):c.G>C, noted as missense protein effect and VarSome classifies it as Likely Benign

STAB2(rs189453513):c.C>G, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs142351376):c.C>T, noted as missense protein effect and VarSome classifies it as Likely Benign

STAB2(rs151219602):c. C>T, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs149382223):c.T>C, noted as missense protein effect and VarSome classifies it as Likely Benign

STAB2(rs2271636):c.G>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs2271638):c.C>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs34699746):c.C>T, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs147053330):c.G>A, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs149524008):c.G>T, noted as missense protein effect and VarSome classifies it as Likely Benign

STAB2(rs116894406):c.G>A, noted as missense protein effect and VarSome classifies it as Likely Benign

STAB2(rs148397037):c.G>A, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs17034336):c.G>A, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs7973658):c.G>A, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs17034433):c.A>C, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs35102665):c.G>A, noted as synonymous protein effect and VarSome classifies it as Likely Benign

STAB2(rs7306642):c.C>A, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs1609860):c.C>A, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs2292688):c.C>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs10778281):c.C>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs2271637):c.C>G, noted as missense protein effect and VarSome classifies it as Benign

STAB2(rs697210):c.T>C, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs11614418):c.C>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs703651):c.C>T, noted as synonymous protein effect and VarSome classifies it as Benign

STAB2(rs697212):c.T>C, noted as synonymous protein effect and VarSome classifies it as Benign

STXBP5(rs144099092):c.C>G, noted as missense protein effect and VarSome classifies it as a VUS.

STXBP5(rs148830578):c.A>G, noted as missense protein effect and VarSome classifies it as a VUS.

STXBP5(rs34324348):c.C>T, noted as synonymous protein effect and VarSome classifies it as a Likely Benign.

STXBP5(rs34677388):c.A>G,noted as synonymous protein effect and VarSome classifies it as Likely Benign.

STXBP5(rs9390459):c.G>A, noted as synonymous protein effect and VarSome classifies it as Benign.

STXBP5(rs1039084):c.A>G, noted as missense protein effect and VarSome classifies it as Benign.

Disease: Von-willebrand Disorder Type 2B, Noncanonical

Patient: 55 YO, Italian male

Note: these heterozygous variants are in cis mutations

Variant1: VWF NM_000552.5 c.2771G>A p.(R924Q), in exon 21, D'D3 domain affected

Variant2: VWF NM_000552.5 c.6532G>T p.(A2178S), in exon 37, D4 domain affected

Phenotypes: Mucosal and cutaneous bleeding, low VWF antigent and VWF activity, mild thrombocytopenia, increased ristocetin-induced platelet aggregation, deficiency in high-molecular-weight multimers. Epistaxis, repeated GI bleeding, easy bruising, ISTH BAT score of 7.

Note: Proband initially diagnosed with VWD type 1 in 2010 but later re-diagnosed as VWD-Type 2.

Family: No reported family history of bleeding, parents unable to be included in family work-up as they were deceased by time of study. Paternity test was performed for family, parental link established. Patient's daughter does not present the same mutation noted in proband but has heterozygous polymorphic variant inherited from mother which is: VWF NM_000552.5 c.3379C>T p.(P1127S), in exon 25. Daughter did not show menorrhagia or hemorrhagic disorder except for large hematoma on the thigh after trauma of moderate intensity.

Molecular workup: Paternity test, Sanger-sequencing to validate genetic variants, multimer analysis with electrophoresis, platelet aggregation analysis with Ristocetin, electron micrographs to observe conformation differences.

Prediction workup: Structural analysis with I-TASSER modeling program to identify perturbed structure. A2178S is predicted as tolerated in all in-silico systems used.

Database Information: Effect of the R924Q mutation is noted in literature database but has contradicting reports of effects altering VWF levels. Some studies do report it as a polymorphic variant

Variant is present in dbSNP database (rs33978901). MAF in European population 0.01< MAF< 0.02

Effect of A2178S variant is present in dbSNP database (rs34230288), MAF = 0.02 in European population.

Disease: Von Willebrand Disease (VWD)

Patient(s): Found in 2 families

Variant: VWF NM_000552.5: c.2311A>G, p.(M771V Homozygous variant in exon 18 (VWF D' domain; 8 residues down from proteolytic VWFpp furin cleavage site)

Family: In family 1 there are 4 homozygous patients (2 male and 2 female), and one heterozygous patient (1 female). The affected females are denoted as person 1 and person 4 and the affected males are person 2 and person 3. There are three WT family members (1 female and 2 male), grandparents of these members are of unknown genotype including a daughter of an affected female and a WT male. Note here that in the family a p.R2663P variant has co-segregated with the above-mentioned variant but is not suspected to be the pathogenic driver of resulting bleeding tendency.

In family 2 the parents of the homozygous affected male are of unknown genotype. The affected male is denoted as person 7.

Phenotypes: Person 1- nose bleed, skin bleed, GI bleeding, oral cavity bleeds, Menorrhagia, muscle bleeding, and joint bleeding. Receives on-demand treatment for bleeding.

Person 2-Nose bleed, skin bleed, bleeding from small wounds, oral cavity bleeds, bleeding after tooth extraction, joint bleeding. Received prophylactic treatment, reduced to on-demand treatment after a few years.

Person 3-Nose bleed, skin bleed, oral cavity bleeds, bleeding after tooth extraction, muscle bleeding. Receives on-demand treatment for bleeding phenotype.

Person 4- Nose bleed, bleeding from small wounds, oral cavity bleed, bleeding after tooth extraction, joint bleeding. Received prophylactic treatment that was increased after her menarche.

Person 7- Nose bleed, oral cavity bleeds, bleeding after surgery or trauma, joint bleeding. Previously on prophylaxis, now managing bleeding with on-demand treatment.

Note that both the p.R2663P co-segregated variant and p.M771V variant are reported in NCBI dbSNP database but functional effect not yet established.

NGS confirmed the genotype of all study participants.

Disease: Von-willebrand Disorder Type 3

Patient: 26 yo, female

Variant: VWF NM_000552.5 c:997+118 T>G g.(6073501 A>C), homozygous, intronic

Phenotypes: No detectable VWF in plasma, early onset bleeding complications, epistaxis, easy bruising, bleeding following injury, menorrhagia, iron-deficient anemia

Note: underwent prophylaxis replacement therapy, on-demand antihemorrhagic treatments, oral contraceptives, and replacement therapy.

Family: not mentioned

Predictions:

VEP SpliceAI tool predicted variant likely deleterious (delta score 0.95)

Used Polyphen-2 and SIFT which determined pathogenic likelihood.

Neural Network Splicing, Alternative Splice Site Predictor, plug-in MaxEnt(For 5' donor site) of Human Splicing Finder all concur this variant can create a new donor splice site in intron 8. Contains premature stop codon and susceptible to NMD.

Functional work:

qRT-PCR performed to identify levels of VWF in IP-derived endothelial cells.

histochemical immunostaining for IP-derived endothelial cells confirm no VWF production, only a residual amount present. Suggests leaky mutation.

performed RNA sequencing to assess co-regulated gene networks

Disorder studied: Type 1 von Willebrand disease (T1-VWD).

Type of study: Translational

Model organism: Mouse (inbred strains) Obtained from Jackson Laboratory

Analyses:

VWF plasma protein quantitation (ELISA)

Hertiability calculations

PCR genotyping

QTL analysis

Allele-specific primer extension analysis

Results:

Identified new modifier of VWF known as (Mvwf5). Also found two loci unliked to Vwf known as (Mvwf6-7)

Mice with this variant displayed statistically significant decrease in VWF levels, recapitulating the decreasing patterns displayed in humans.

However, another strain of inbred mice with a different mutation did not show an age-dependent decrease in VWF. Suggests strain-specific differences in regulation of VWF levels over time.

Mvwf5 is a cis-regulatory variant altering Vwf mRNA expression.

This is a natural variant of the Vwf allele among inbred strains of mice. Found this variant causes elevation in steady-state levels of Vwf mRNA.

Authors state findings show equivalent of of type 1 VWD is remarkably common in mice and humans. ALso state the Mvwf1 analysis in wild mouse populations suggest this locus is under selective pressure.

Of the 5 potential modifier loci identified, 3 display conservation of synteny with potential human modifier loci.

Disease: Platelet-type Von-willebrand Disorder (PT-VWD)

Patient: 17 yo, male, adopted

Variant: GP1BA NM_000173.7: c:580C>T p.(P.Leu194Phe), Heterozygous, gain-of-function

Phenotypes: moderate bleeding phenotype, ISTH-BAT bleeding score of 3, recurrent epistaxis, easy bruising, mild thrombocytopenia

Family: Adopted, no other family history mentioned, segregation studies not performed.

Genetic analysis performed: found variant in GP1BA, results obtained by sanger sequencing.

Variant present in gnomAD(rs368111193): low allele frequency, contradictory classifications

Variant is not present in ClinVar, LOVD, or HGMD databases

According to this paper, ACMG guidelines classified this variant as a VUS.

This paper entered it into Clinvar (var ID 1693270)

Disease: Von Willebrand Disease (VWD) type 1

Patient(s): 13 yo, female and 14 yo, female, both Italian

Variant: VWF NM_000552.5: c.820A>C p. (Thr274Pro)

Dominant negative effect

Heterozygous carrier

Variant located in the D1 domain on VWF

Phenotypes:

heterozygous carriers have no bleeding history

reduced VWF levels compatible with diagnosis of VWD type 1

increased FVIII:C/VWF:Ag ratio, suggests reduced VWF synthesis/secretion as possible phathophysiological mechanism

Normal VWFpp/VWF:Ag ratio

Modest alteration of multimeric pattern in plasma and platelet multimers

plasma VWF showed slight increase of LMWM and decrease of IMWM and HMWM

Platelet VWF showed quantitative decrease of IMWM, HMWM, and UL multimers

In silico analysis:

SIFT, ALIGN, GVD Polyphen 2.0, SNP&GO, Mutation Taster, Pmut all suggest damaging consequences.

PROVEAN and Effect suggest neutral effect

according to ACMG guidelines this variant was classified as pathogenic

Disease: platelet-type von Willebrand disease (PT-VWD)

Patient: 14 yo, Male

Variant: GP1BA NM_000173.7:c.389G>A p.(Arg127Gln), Heterozygous, Gain-of-Function (GOF)

Located in LRR5 domain of GP1BA

Family: Mother did not refer any bleeding symptoms (variant absent in mother) Father not available for collection of clinical history or platelet function testing