Phenotype/genotype correlation in 670 index cases (IC) patients with von Willebrand disease (VWD). Among 670 IC, after second level phenotypic assays and direct sequencing of VWF gene, 648 patients exhibited a genotype supporting their phenotype: 151 patients had type 1 VWD, 121 patients type 2A, 112 patients type 2B, 127 patients type 2M, 81 patients type 2N, 49 patients type 3, and 7 patients undetermined (U) VWD. In contrast, after direct sequencing, the genotype was not supporting the phenotype in 22 patients (17 patients with no mutation and 5 patients with only 1 mutation although recessive inheritance) who thus underwent Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. MLPA helped identifying large deletions, insertions, and duplications in 14 patients consisting in 10 type 1, 1 type 2A (IIC), and 3 type 3. Finally, 8 patients remained with a genotype either not explaining their phenotype (6 type 1 patients with no mutation found) or only partially supporting their phenotype (2 type 3 patients with a single mutation found).IC = index cases, MLPA = multiplex ligation-dependent probe amplification, VWD = von Willebrand disease.