Increased fertility as an eventual mechanism maintaining high frequencies of hemoglobinopathies in Brazil

Michelle Marcondes Mazzi Rosa Chelminsky Teixeira Luís Alberto Magna Antonio Sérgio Ramalho About the authors

Abstract Increased fertility of heterozygous women is one of the suggested processes maintaining balanced polymorphism of the hemoglobinopathies in some countries. In the present work we studied the fertility of 68 b-thalassemia trait (heterozygous AT) and 53 sickle cell trait (heterozygous AS) women married with normal hemoglobin husbands. The average number of children per heterozygous AT and AS women (2.7647 and 3.0755, respectively) did not differ significantly from those observed among their control sisters with normal hemoglobin (2.3778 and 3, respectively). In addition, it was not observed a significant difference between the proportion of married women without children between the heterozygous women and their control sisters. The results herein presented hence does not support the hypothesis of increased fertility of heterozygous women as being a homeostatic mechanism able to maintain the polymorphism of either b-thalassemia and hemoglobin S in Brazil.

Hemoglobinopathies; Differential fertility; Balanced polymorphisms

Sociedade Brasileira de Patologia Clínica, Rua Dois de Dezembro,78/909 - Catete, CEP: 22220-040v - Rio de Janeiro - RJ, Tel.: +55 21 - 3077-1400 / 3077-1408, Fax.: +55 21 - 2205-3386 - Rio de Janeiro - RJ - Brazil