A 19-year-old woman was diagnosed with a reduced coagulation factor VIII activity of 30% after bleeding complications from wisdom tooth surgery
Case: Female, 19 y.o., ethnicity unknown.
DiseaseAssertion: VWD2N
FamilyInfo: Proband has one older symptomatic sister who shares an identical compound heterozygous genotype, presenting with a mild bleeding tendency, reduced FVIII activity (20-30%), and severely reduced FVIII binding (<2%). The family features one younger unaffected sister who tested negative for both variants, and an unaffected carrier mother. Both parents had normal factor VIII, and there was no male relative with reduced factor VIII or bleeding symptoms.
ParentalGenotype(s): Mother is heterozygous for the c.2561G>A (p.R854Q) variant, negative for the c.2402G>A (p.S801N) variant, and has normal baseline factor VIII levels, confirming the sisters' variants are in trans. Father unavailable/not tested.
CasePresentingHPOs: HP:0004846 (Prolonged bleeding after surgery), HP:0003645 (Prolonged partial thromboplastin time).
CaseHPOFreeText: Index patient experienced bleeding complications following wisdom tooth surgery. Factor VIII binding activity is reduced at 32%. Reduced coagulation factor VIII activity (30%). Prolonged activated partial thromboplastin time (aPTT) of 37 seconds.
CaseNOTHPOs: HP:0001873 (Thrombocytopenia), HP:0012147 (Reduced quantity of von Willebrand factor), HP:0030130 (Impaired von Willebrand factor collagen binding activity).
CaseNOTHPOFreeText: Normal vWF antigen (vWF:Ag) levels (101%), normal vWF activity (116%), normal vWF-collagen-binding activity (104%), normal vWF multimer distribution structures, normal hemoglobin level (128 g/L), and normal Prothrombin Time (PT/QUICK) of 83%.
CasePreviousTesting: Siblings did not carry any known mutations in the F8 gene or the LMAN1 and MCFD2 genes (which encode for endoplasmic reticulum carrier proteins of coagulation factors V and VIII).
GenotypingMethod: Direct sequence analysis of VWF exons 18-20.
PreviouslyPublished: NA.
Gene: VWF
HGNCID: HGNC:12726
Variant: Heterozygous c.2561G>A (p.R854Q) and heterozygous c.2402G>A (p.S801N).
HGVS: (1) NM_000552.5:c.2561G>A (p.Arg854Gln) (2) NM_000552.5:c.2402G>A (p.Ser801Asn)
ClinVarID: (1) 296 (2) NA
CAID: (1) NA (2) CA383522023
gnomAD: (1) MAF of 0.005974 in the European (non-Finnish) population https://gnomad.broadinstitute.org/variant/12-6034812-C-T?dataset=gnomad_r4
(2) MAF of 0.00001098 in the South Asian population https://gnomad.broadinstitute.org/variant/12-6044331-C-T?dataset=gnomad_r4