Holmsen et al. (1987) studied a family of Chinese ancestry with marked bleeding tendencies and found that aggregation responses to low concentrations of ADP, epinephrine, collagen, and cationophore A23187 in platelets were virtually absent. The platelets from the ... Holmsen et al. (1987) studied a family of Chinese ancestry with marked bleeding tendencies and found that aggregation responses to low concentrations of ADP, epinephrine, collagen, and cationophore A23187 in platelets were virtually absent. The platelets from the patients had normal stores of secretable constituents, but secretion of adenine nucleotides and acid hydrolases in response to low concentrations of thrombin and A23187 was drastically reduced compared to normal platelets; secretion of platelet factor 4 was normal. Frequent epistaxis was a leading manifestation. Thrombocytopenia of moderate degree was present in some.