Von Willebrand disease type 2B with a novel mutation in the VWF gene

Abstract

We report a 38-year-old woman who presented with a subdural hematoma after minor facial trauma in a stressful situation. The laboratory data showed a subnormal platelet count (166×10 9 /L), VWF:RCo activity was 45% and VWF:Ag was 53% with a VWF:RCo/VWF Ag ratio of 0.79. Hemostasis results and gene analysis revealed von Willebrand disease (VWD) type 2B with normal multimers and a novel mutation c.4136 G>T (R1379L), which appears to be a novel mutation of VWD type 2B that is mainly diagnosed with hypersensitivity to ristocetin and an hyperfixation of platelet Willebrand to a recombinant Gp1b. SIMILAR CASES PUBLISHED: None.

Guideline for laboratory diagnosis and monitoring of von Willebrand disease: A joint guideline from the United Kingdom Haemophilia Centre Doctors' Organisation and the British Society for Haematology

“…[94][95][96] VWF multimer analysis is not only the definitive assay for differentiation between type 2A or 2B and 2M VWD but can also be useful in distinction between type 3 and very low type 1 VWD or in individuals with AVWS. 7,66,[97][98][99] However, it must be recognised that results may be incongruent with some types of VWD. There have been reports of normal multimers in type 2B VWD 28,98 and some minor loss of HMWM linked to certain genetic variants have been reported in type 2M with the GPIb-binding type variants; normal multimer patterns are reported in type 2M with the CB-type variants 66,67,73,100 ; ultra-large molecular weight multimers can be seen in type 1C VWD, 101 thrombotic thrombocytopenic purpura 73 and in some patients with type 2M VWD.…”

“…VWF multimer analysis is not only the definitive assay for differentiation between type 2A or 2B and 2M VWD but can also be useful in distinction between type 3 and very low type 1 VWD or in individuals with AVWS 7,66,97–99 . However, it must be recognised that results may be incongruent with some types of VWD.…”

“…However, it must be recognised that results may be incongruent with some types of VWD. There have been reports of normal multimers in type 2B VWD 28,98 and some minor loss of HMWM linked to certain genetic variants have been reported in type 2M with the GPIb‐binding type variants; normal multimer patterns are reported in type 2M with the CB‐type variants 66,67,73,100 ; ultra‐large molecular weight multimers can be seen in type 1C VWD, 101 thrombotic thrombocytopenic purpura 73 and in some patients with type 2M VWD 102 …”