These are caused mainly by defects of the membrane receptors (Glanzmann thrombasthenia, P2Y12 deficiency, glycoprotein VI (GPVI) deficiency, among others), granules (Hermansky–Pudlak syndrome, among others), elements involved in signal transduction, or other defects of the biochemical platelet machinery (such as thromboxane A synthase 1 (TBXAS1) deficiency) [15]. The gene discussed is TBXAS1; the disease is Glanzmann thrombasthenia.