RESUMO
Linked DNA polymorphisms can be used to study the evolution of structural gene mutations. Both the beta S-(beta 6Glu leads to Val) and beta C-(beta 6Glu leads to Lys) genes are common in West Africa. We have analyzed their linkage to a polymorphic Hpa 1 site appearing 3' to the beta-globin gene locus in selected populations from Wes Africa. A large reservoir of beta A-genes linked to 13-kilobase Hpa 1 fragments with a frequency of 17-18% has been identified. In addition, the beta S- and beta C-genes in Togo are found to be tightly linked to the 13-kilobase Hpa 1 fragment, whereas 72% of the beta S-genes in the Ivory Coast reside on the 7.6-kilobase Hpa 1 fragment. These studies are consistent with the selection and expansion of two different chromosomes bearing beta S-genes in at least two physically close, but ethnically separate regions of West Africa, with subsequent diffusion to North, Equatorial, and East Africa.
Assuntos
Anemia Falciforme/genética , Evolução Biológica , Hemoglobina Falciforme/genética , África/etnologia , Enzimas de Restrição do DNA , Genes , Genética Populacional , Humanos , Polimorfismo GenéticoRESUMO
A Basque Spanish family with heterozygous deltabeta-thalassemia is described. Patients with this anomaly usually present hematological findings observed in classical beta-thalassemia, but clinical conditions and unbalanced chain synthesis are less severe. Our propositus, however, presented clinical and biosynthetic data similar to those described in thalassemia intermedia. A family study was also performed.
Assuntos
Hemoglobinas/biossíntese , Talassemia/sangue , Adolescente , Adulto , Criança , Feminino , Hemoglobina Fetal/análise , Hemoglobina Fetal/biossíntese , Hemoglobina Fetal/genética , Hematócrito , Hemoglobina A2/análise , Hemoglobina A2/biossíntese , Hemoglobina A2/genética , Hemoglobinas/análise , Hemoglobinas/genética , Humanos , Masculino , Pessoa de Meia-Idade , Espanha , Talassemia/genéticaRESUMO
In this paper are brought the results obtained in two Parisian hospitals during a survey of abnormal hemoglobins in 540 immigrant workers coming from Africa, mostly from Mali, Mauritania and Senegal. All the subjects investigated were male and between 20 and 40 years old. The studies were performed following internationally standardized technics. The most frequent abnormalities were: Hb S found in 16.3%, Hb C (6.6%), alpha-thalassemia trait (3.1%) and beta-thalassemia trait (3.1%). Some rare abnormalities were also found: delta-chain variants, hereditary persistance of foetal hemoglobin, Hb Hope and Hb Grady. This work emphasizes the high frequency of the different hemoglobin disorders in this population. The easy diagnostic of electrophoretically detectable variants is compared to the more complex situation of thalassemia leading probably to an under estimation of the percentage.