In the differential diagnosis of unexplained excessive bleeding, we considered inherited platelet function disorders, including Wiskott-Aldrich syndrome, Glanzmann's thrombasthenia, Bernard-Soulier syndrome, ADP receptor defect, von Willebrand disease, idiopathic dense-granule disorder, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and grey platelet syndrome [7]. This evidence concerns the gene P2RY1 and Chédiak-Higashi syndrome.