Prevalence and Clinico-Hematologic Scenario of Von Willebrand Disease in a Population of Filipinos with Bleeding Tendency

• Prevalence and Clinico-Hematologic Scenario of Von Willebrand Disease in a Population of Filipinos with Bleeding Tendency

AUTHOR(S)

Mary Ng CHUA^＊１, Maria Suga A. DIOKO^＊２ and Lorena SANTOS^＊３

*1 Section of Pediatric Hematology-Oncology, National Hemophilia Center,
    Santo Tomas University Hospital
*2 Section of Pediatric Hematology-Oncology, Department of Pediatrics,
    Santo Tomas University Hospital
*3 National Hemophilia Center, Santo Tomas University Hospital

SUMMARY

Von Willebrand Disease ( VWD ) is the most common inherited bleeding disorder. It is defined as a deficiency of von Willebrand Factor ( VWF ) function causing impaired hemostasis. VWF functions as a carrier protein for coagulation factor VIII ( FVIII ) and as adhesive protein for vessel wall-platelet interaction. Studies in a predominantly pediatric population reveal that the prevalence of VWD is 0.8 - 1.3%. There are 3 main types of VWD based on the quantitative or qualitative defects in VWF.

Ninety-nine patients with bleeding manifestations were referred to the National Hemophilia Center from all over the Philippines. Patients who fulfilled the inclusion and exclusion criteria with at least 2 symptoms consistent with VWD underwent initial screening tests: a complete blood count with actual platelet, blood typing, bleeding time, prothrombin time and activated partial thromboplastin time. Laboratory tests to diagnose VWD included FVIII, VWF antigen ( VWF : Ag ) and ristocetin cofactor ( VWF : RCo ). Thirty-four patients ( 34.34% ) with bleeding manifestations had VWD. Patients with or without VWD were comparable as to age, sex distribution, family history of bleeding, blood type and bleeding manifestations.

Among the patients with VWD, 11 ( 32.35% ) had Type 1 VWD and 23 ( 67.65% ) had Type 2 VWD. No Type 3 VWD was observed. The mean FVIII, VWF:Ag and VWF:RCo were decreased in Type 1 VWD. In Type 2 VWD, the mean VWF : Ag was normal while the mean FVIII and VWF: RCo were decreased.

The study suggests that among patients with bleeding tendency in the Philippines, there is a high proportion of patients with VWD.

KEY WORDS

Von Willebrand disease ( VWD ), Screening tests, Von Willebrand factor ( VWF ) ristocetin co-factor