Since GPIb-IX-V is composed of four subunits encoded by four separate genes, glycoprotein Ib platelet alpha subunit (GP1BA), glycoprotein Ib platelet beta subunit (GP1BB), glycoprotein IX platelet (GP9), and glycoprotein V platelet (GP5), the molecular basis of BSS is characterized by locus and allelic heterogeneity [8], although, until today no disease causing the GP5 variant has been identified. The gene discussed is GP9; the disease is Bernard-Soulier syndrome.