Identification and characterization of a novel P2Y12 variant in a patient diagnosed with type 1 von Willebrand disease in the European MCMDM-1VWD study

• Published in: Blood Vol. 113; no. 17; pp. 4110 - 4113
• Main Authors: Daly, Martina E., Dawood, Ban B., Lester, William A., Peake, Ian R., Rodeghiero, Francesco, Goodeve, Anne C., Makris, Michael, Wilde, Jonathan T., Mumford, Andrew D., Watson, Stephen P., Mundell, Stuart J.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 23.04.2009; Americain Society of Hematology
• Subjects: Biological and medical sciences; Hematologic and hematopoietic diseases; Medical sciences; Europe; Human; Variant; P2Y12 purinergic receptor; Genetic variability; Type 1 Willebrand disease; Hematology; Genotype; Diagnosis
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2008-11-190850

We investigated whether defects in the P2Y12 ADP receptor gene (P2RY12) contribute to the bleeding tendency in 92 index cases enrolled in the European MCMDM-1VWD study. A heterozygous mutation, predicting a lysine to glutamate (K174E) substitution in P2Y12, was identified in one case with mild type 1 von Willebrand disease (VWD) and a VWF defect. Platelets from the index case and relatives carrying the K174E defect changed shape in response to ADP, but showed reduced and reversible aggregation in response to 10 μM ADP, unlike the maximal, sustained aggregation observed in controls. The reduced response was associated with an approximate 50% reduction in binding of [3H]2MeS-ADP to P2Y12, whereas binding to the P2Y1 receptor was normal. A hemagglutinin-tagged K174E P2Y12 variant showed surface expression in CHO cells, markedly reduced binding to [3H]2MeS-ADP, and minimal ADP-mediated inhibition of forskolin-induced adenylyl cyclase activity. Our results provide further evidence for locus heterogeneity in type 1 VWD.