Aumento de fertilidade como eventual mecanismo de manutenção das altas freqüências de hemoglobinopatias no Brasil

Abstract

y unitermos key words resumo O aumento da fertilidade das heterozigotas é um dos mecanismos sugeridos na manutenção do polimorfismo balanceado das hemoglobinopatias em alguns países. No presente trabalho, estudamos a fertilidade de 68 portadoras do traço talassêmico β (heterozigotas AT) e de 53 portadoras do traço falciforme (heterozigotas AS) casadas com indivíduos com hemoglobina normal. O número médio de filhos por heterozigotas AT e AS (2,7647 e 3,0755, respectivamente) não diferiu significativamente do observado entre suas irmãs com hemoglobina normal (2,3778 e 3, respectivamente). Além disso, também não foi observada diferença significativa, quanto à proporção de mulheres casadas sem filhos, entre as heterozigotas e as suas irmãs. Tais resultados não favorecem, portanto, a hipótese de que o aumento de fertilidade das heterozigotas seja um mecanismo de manutenção do polimorfismo da talassemia β e da hemoglobina S no Brasil. Hemoglobinopatias Fertilidade diferencial Polimorfismos balanceadosabstract 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 β-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 β-thalassemia and hemoglobin S in Brazil. Hemoglobinopathies Differential fertilityBalanced polymorphisms

Differences in the hemoglobin cut-off point for the diagnosis of anemia as a function of race/color

“…8 It is known that hemoglobin levels vary according to age, gender, different stages of pregnancy, smoking Differences in the hemoglobin cut-off point for the diagnosis of anemia as a function of race/color of one of the globin chains that make up hemoglobin. [15][16][17] Both iron deficiency anemia and thalassemia cause reduction in hemoglobin levels, microcytosis, and hypochromia, however, the transferrin saturation is invariably high in thalassemia, which is a useful differential parameter. 18 Thus, none of these hemoglobinopathies (sickle cell anemia or thalassemia) can explain the low levels of hemoglobin in blacks.…”