Reduced platelet MAO activity in healthy male students with blood group O

– The association between the two genetic markers of affective disorders, ABO blood group system and platelet MAO (mono-amine oxidase) activity was studied in 70 healthy young males. The platelet MAO activity of subjects with blood type O was significantly lower than that of subjects with blood type A and with blood types A+AB+B together. This finding could constitute a “bridge” between the two genetic approaches to affective disorders.