[The phenotype Hp O in several African and Central American populations]

This work shows the higher probability for some individuals of having Hp O phenotype: that is, children under twelve, and individual carriers of haemoglobin S (haemoglobin D carriers do not present this characteristic). This observation appears as a confirmation of the hypotheses explaining Hp O phenotype as a consequence of haemolytic anaemia. Besides, the test of two genetic models taking into account both Hp O and Hp21 M phenotypes leads to strong difficulties due to a certain irregularity of "haptoglobin" genetic system.