GENOTYPIC DIAGNOSIS OF VWD: PRELIMINARY RESULTS IN THE ANALYSIS OF EXON 28

WOODS AI; KEMPFER A C; KELLER L; CALDERAZZO JC; SANCHEZ-LUCEROS A; PAIVA J; LAZZARI MA

Boston

Congreso; XXII Congress of the International Society on Thrombosis and Haemostasis; 2009

Abstract: In the exon 28 of gene encoding for von Willebrand factor (VWF) are located 78.8% of the mutations (Mt) related to von Willebrand disease (VWD) type 2A, 100% of 2B, 96% of 2M, 32% of type 1, 16% of type 3. Our aim is to detect Mut in exon 28 of patients (P) with VWF:RCoA (V1316M). D: VWD 2B. Database: VWD 2B. Unrelated P3, P4, P5: normal multimers. Mt: heterozygous 3943C>T (R1315C). D: VWD 2M. Database: type 1, 3, 2A, 2M, unclassified VWD. P6, P7 (father), P8 (sister): normal multimers. Mt: heterozygous 4883T>C (I1628T). D: VWD 2M. Database: VWD 2A. Related P9, P10: normal multimers. Mt: homozygous T4120 (C1374). D: VWD 2M. Database: VWD 2A/2M. Discrepancies between the VWD variants and the Mt have been reported by different groups. It could be due to either the limitations in the current methods employed, or to the fact that some mutations don?t specifically define a VWD variant. Presence of certain mutations, as isolated finding, doesn?t seem to define a specific variant. Multimers can help to discriminate between 2A and 2M, and between 2M and severe type 1 variants. These considerations are showing a serious diagnostic problem that can be solved by analyzing in each patient, all the available phenotypic and genotypic parameters without ever ignoring the multimeric pattern, in order to arrive at an accurate diagnosis of VWD variants