Aggregation in a participant diagnosed with a TxA₂ pathway defect. Aggregation in a participant (p) diagnosed with a TxA₂ pathway defect. The TxA₂ pathway defect also results in the abolition of response to arachidonic acid (1mM) and impairment in response to other agonists, including ADP and adrenaline, but not to U46619, indicating a defect in arachidonic acid metabolism. “c” indicates control (healthy volunteer). The pattern of aggregation is representative of other participants diagnosed with a defect in arachidonic metabolism.