Bleeding Disorder Due To P2y12 Defect

P2Y12 defect is a rare hemorrhagic disorder characterized by mild to moderate bleeding diathesis with easy bruising, mucosal bleedings, and excessive post-operative hemorrhage due to defect of the platelet P2Y12 receptor resulting in selective impairment of platelet responses to adenosine diphosphate.

Epidemiology

To date, 14 patients have been described in the world literature.

Clinical description

P2Y12 defect is a congenital disorder that manifests by mildly to severely prolonged bleeding time, easy bruising, mucosal bleeding (epistaxis, gastric mucosa bleeding, gum bleeding, etc.), menorrhagia, and bleeding complications after trauma and minor or major surgery.

Etiology

P2Y12 defect is caused by mutations in the P2RY12 gene (3q24-q25) which result in the premature truncation of the P2Y12 receptor or in the synthesis of a dysfunctional P2Y12 receptor. ADP activates platelets through its interaction with two G protein-coupled receptors, P2Y1 and P2Y12. The P2Y1 receptor mediates mobilization of ionized calcium and is responsible for ADP-induced shape change andweak and transient aggregation, while the P2Y12 receptor is responsible for the completion and amplification of the response to ADP and to all platelet agonists including thromboxane A2, thrombin, and collagen. P2Y12 receptor thus plays a central role in the formation and stabilization of a thrombus.

Genetic counseling

Transmission of P2Y12 deficiency is autosomal recessive. Genetic counseling should be offered to at-risk couples (where both individuals are carriers of a disease-causing mutation) informing them of the 25% risk of having an affected child.