title: Prevalence and molecular heterogeneity of alfa+ thalassemia in two tribal populations from Andhra Pradesh, India.
abstract: We describe here the screening of a small group of apparently healthy individuals belonging to the tribal communities of Koya Dora and Konda Reddi. A remarkably high incidence of deletion and nondeletion alpha + thalassemia mutants has been found with allele frequencies and distributions characteristic to each tribe. We have confirmed the strict relationship between Hb S levels and the number of alpha globin genes in double heterozygotes for the S gene and alpha thalassemia. In this population sample we did not find either heterozygous carriers of alpha 0 thalassemia (deletion of both alpha genes in "cis") or individuals showing hemolytic anemia due to inactivation of three alpha-globin genes (Hb H disease). Selection by malaria is most probably responsible for the prevalence of the various alpha + thalassemia haplotypes among the two tribal populations of Andhra Pradesh.
authors.affiliation: Department of Human Genetics, Sylvius Laboratoria, University of Leiden, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Fodde
authors.forename: M
authors.initials: M
authors.lastname: Losekoot
authors.forename: M H
authors.initials: MH
authors.lastname: van den Broek
authors.forename: M
authors.initials: M
authors.lastname: Oldenburg
authors.forename: N
authors.initials: N
authors.lastname: Rashida
authors.forename: A
authors.initials: A
authors.lastname: Schreuder
authors.forename: J T
authors.initials: JT
authors.lastname: Wijnen
authors.forename: P C
authors.initials: PC
authors.lastname: Giordano
authors.forename: N V
authors.initials: NV
authors.lastname: Nayudu
authors.forename: P M
authors.initials: PM
authors.lastname: Khan
mesh_terms: D005006:Ethnicity; D005914:Globins / Q000235:genetics*; D006239:Haplotypes; D006451:Hemoglobin, Sickle / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D007194:India; D015183:Restriction Mapping; D012805:Sickle Cell Trait / Q000453:epidemiology / Q000235:genetics; D013789:Thalassemia / Q000453:epidemiology / Q000235:genetics*
chemical_list: D006451:Hemoglobin, Sickle; D005914:Globins