Types and Sub Types of Von Willebrand Disease Classified on the Basis of Multimer Analysis

Introduction: Von Willebrand disease is a common genetically inherited bleeding disorder. Types of VWD classified on the basis of coagulation factor assays but it cannot characterize further subtypes or verdict the quality and quantity of VWF. Multimer analysis facilitates the classification and prerequisite parameter to accurate diagnosis of VWD.

Objective: To characterize the type and subtypes of VWD type I and II on the basis of laboratory data and analysis of VWF multimer structure.

Setting: NIBD Karachi, University of Bonn Germany, Children Hospital & Chughtai Lab Lahore, PAEC Islamabad and HMC Peshawar.

Material And Method: VWF Ag, Ricof, FVIII, Glycoprotein Ib and multimer analysis of VWD plasma on 1.6% medium resolution SDS-agarose gel electrophoresis was carried out, and then VWF multimer were transferred on nitrocellulose membrane. Incubated nitrocellulose membrane with using polyclonal rabbit anti-human VWF antibody and Goat anti-rabbit IgG HRP conjugate then protein detected by immune reaction after evaluation of the membrane under luminescence.

Results: We studied 57 index patients, 2(3.5%) type I, 4(7.01%) type II, 3(5.26%) unclassified and 48(15.78%) were type III vWD. In type I,II, unclassified and III mean vWF Ag was 52.28, 35.15, 54.5 , 5.7 IU/dl, vWF RCo: 19.5, 18, 38.8, 7.22 IU/dl, vWF Ag/ RCof: 0.655, 0.393, 0.74, 0.55, FVIII 69, 25.7, 61.7, 7.22 IU/dl and GpIb: 27.25, 19.8, 39.8, 4.1. Significant loss of large multimers in type II while multimers were subtle in 2 cases, normal pattern in type I and entirely absence of multimers pattern in case of type III observed.

Conclusion: Types and subtypes of VWD classified on the basis of concentration and distribution of vWF multimer by functional and immunological assays but single test is not enough for appropriate diagnosis. We need molecular genetics for von Willebrand disease for further diagnosis.