[Structural variants of hemoglobin in Ibero-America].

Structural hemoglobin variants are reviewed for Iberoamerica; specially in Latin America, they reflect racial composition and geographic origin. Latin American genetic composition is a function of ethnic composition in each country (mainly Africans and Spaniards, and the "indians" or native peoples). For this reason the distribution of hemoglobin variants has been greatly affected by the individual and population movements, specially as a result of the 18th and 19th century African slave trade. Scientific, sanitary, social and cultural factors explain (at least for Latin America and Portugal), a quantitative and qualitative subestimation of the structural variants of hemoglobin. In Spain, which has extensive research on the subject, the Caucasian variant number is known to be high, compared with Latin America and Portugal. Concerning origin and prevalence of hemoglobin polymorphism, the only established positive selection force is malaria falciparum. In Iberoamerica, the Hb S, as the major polymorphism and the HbC, have the greatest clinical and anthropological importance. Nevertheless, most variants are rare (found in an individual person or a particular family). Other minor Iberoamerica polymorphisms are the Hb E and D-Punjab, from Asia; and the Hb Korle-Bu, G-Philadelphia and A2 from Africa.