A new case of platelet‐type von Willebrand disease supports the recent findings of gain‐of‐function GP1BA variants outside the C‐terminal disulphide loop enhances affinity for von Willebrand factorCatarina Monteiro, Ana Gonçalves, Mónica Pereira, Catarina Lau, Sara Morais, Rosário Santos
Platelet‐type von Willebrand disease (PT‐VWD) is a rare autosomal dominant bleeding disorder characterized by an increased ristocetin‐induced platelet aggregation (RIPA) and enhanced affinity of platelet glycoprotein Ibα (GPIbα) to von Willebrand factor (VWF). To date, only seven variants have been described with this gain‐of‐function effect, most of them located in the C‐terminal disulphide loop of the VWF‐binding domain of GPIbα. We herein describe a patient with moderate bleeding symptoms, mild thrombocytopenia and increased RIPA. By direct sequencing of GP1BA, a novel leucine‐rich repeat heterozygous variant was identified (c.580C>T; predictably p.Leu194Phe), strongly suggestive as being the underlying cause for the PT‐VWD phenotype of our patient.