title: Prevalence of -alpha(3.7) and alpha alpha alpha(anti3.7) alleles in sickle cell trait and beta-thalassemia patients in Mexico.
abstract: The aim of this study was to determine the frequency of alpha-globin gene mutations in three groups of Mexican unrelated individuals. The first two groups were normal and sickle cell trait individuals from the Costa Chica region, a place with a 12.8% frequency of HbS carriers, and the third group comprised of Mexican mestizo patients with beta-thalassemia. We searched for -alpha(3.7) and -alpha(4.2) alpha(+)-thalassemia deletion alleles, as well as the alpha alpha alpha(anti3.7) triplication through long-gap PCR. The alleles -alpha(3.7) and alpha alpha alpha(anti3.7) were found in the heterozygote state only; 19% of the normal subjects had the -alpha(3.7) allele, and 2% showed the alpha alpha alpha(anti3.7) allele. In individuals with the sickle cell trait, 17% had the -alpha(3.7) deletion, and the alpha alpha alpha(anti3.7) triplication was observed in 3% of these individuals. We revealed that 16% of the subjects with beta-thalassemia showed the -alpha(3.7) deletion and 28% the alpha alpha alpha(anti3.7) triplication. The -alpha(4.2) deletion was not detected in any individual. The frequency of the -alpha(3.7) allele was roughly the same in the three groups studied; this can be explained by the fact that the three groups have common genes from Africa and the Mediterranean, where a high prevalence of alpha(+)-thalassemia has been observed. To our knowledge, the frequency of alpha alpha alpha(anti3.7) triplication observed in the Mexican beta-thalassemia patients is the highest reported. As the -alpha(3.7) and alpha alpha alpha(anti3.7) alleles are very common in our selected populations, we believe that there is a need to investigate systematically the alpha-globin gene mutations in all hemoglobinopathies in the Mexican population.
authors.affiliation: División de Genética, Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguro Social, Sierra Mojada No. 800, Colonia Independencia, CP 44340, Guadalajara, Jalisco, México.
authors.forename: María Paulina
authors.initials: MP
authors.lastname: Nava
authors.forename: Bertha
authors.initials: B
authors.lastname: Ibarra
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Magaña
authors.forename: María
authors.initials: M
authors.lastname: de la Luz Chávez
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Perea
mesh_terms: D000483:Alleles; D000755:Anemia, Sickle Cell / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D005914:Globins / Q000235:genetics; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D017720:Molecular Epidemiology; D009154:Mutation; D015995:Prevalence; D017086:beta-Thalassemia / Q000235:genetics*
chemical_list: D005914:Globins