[Beta globin haplotypes in hemoglobin S carriers in Colombia]

The hemoglobin S (HbS) mutation is accompanied by other mutations in the region of chromosome 11 known as "beta globin cluster". The pattern of combination of these polymorphisms giving rise to the haplotypes that co-inherit the HbS mutation, are called haplotypes bs, and are of great epidemiological and clinical significance.

The frequencies of major haplotypes associated with S beta-globin gene was determined in Colombian patients heterozygous for hemoglobin S.

As part of the national neonatal screening program at Clínica Colsanitas, located in major cities of Colombia, nearly 1,200 children from different areas of the country were examined for hemoglobinopathies. The sickle cell trait was identified as the most common. S beta-globin gene haplotypes were determined by PCR and restriction enzymes in 33 children with AS hemoglobin electrophoretic patterns (carrier state). In addition, electrophoretic patterns of hemoglobin, fetal hemoglobin levels and hematologic parameters of each individual were identified.

The most frequent haplotypes in Colombia were the Bantú haplotype (36.4 %), followed by Senegal (30.3 %), Benin (21.2 %) and Cameroon (12.1 %) haplotypes. Hemoglobin electrophoresis confirmed the AS phenotype in all patients, and fetal hemoglobin levels below 1%. Other hematological parameters were normal in all cases.

The HbS haplotypes found more frequently in the sample were of African origin, and their distribution varied according to the place of origin of the individual. The most frequent corresponded to the Bantu haplotype.