RESUMO
The hemoglobin disorders are the most common single gene disorders in the world. Previous studies have suggested that they are deeply geographically structured and a variety of genetic determinants influences different clinical phenotypes between patients inheriting identical ß-globin gene mutations. In order to get new insights into the heterogeneity of hemoglobin disorders, we investigated the molecular variations on nuclear genes (i.e. HBB, HBG2, BCL11A, HBS1L and MYB) and mitochondrial DNA control region. This pilot study was carried out on 53 patients belonging to different continents and molecularly classified in 4 subgroup: ß-thalassemia (ß+/ß+, ß0/ß0 and ß+/ß0)(15), sickle cell disease (HbS/HbS)(20), sickle cell/ß-thalassemia (HbS/ß+ or HBS/ß0)(10), and non-thalassemic compound heterozygous (HbS/HbC, HbO-Arab/HbC)(8). This comprehensive phylogenetic analysis provided a clear separation between African and European patients either in nuclear or mitochondrial variations. Notably, informing on the phylogeographic structure of affected individuals, this accurate genetic stratification, could help to optimize the diagnostic algorithm for patients with uncertain or unknown origin.
Assuntos
Anemia Falciforme/genética , Hemoglobinopatias/genética , Proteínas Nucleares/genética , Talassemia beta/genética , DNA Mitocondrial/genética , Feminino , Hemoglobina Fetal/genética , Proteínas de Ligação ao GTP/genética , Variação Genética/genética , Haplótipos/genética , Hemoglobina Falciforme/genética , Hemoglobinopatias/classificação , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/patologia , Humanos , Masculino , Projetos Piloto , Polimorfismo de Nucleotídeo Único/genética , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myb/genética , Proteínas Repressoras/genética , Globinas beta/genéticaRESUMO
The aim of this study was to describe the mutational spectrum of hemoglobinopathies during the period 1988-2015 in Umbria, Central Italy, which has never been considered endemic for these conditions. Twenty-four different ß-globin gene mutations were identified in 188 patients and eight different α-globin gene mutations in 74 patients. Sixty percent ß-thalassemia (ß-thal), 85.0% sickle cell disease, 44.0% Hb S (HBB: c.20A>T)/ß-thal and 85.0% compound heterozygotes for hemoglobin (Hb) variant-carrying patients were diagnosed or molecularly characterized in the last 3 years. Moreover, most homozygous or compound heterozygous patients (84.5%) came from foreign countries, while only 15.5% were of Italian origin. These data are in accordance with the increasing foreign resident population in Umbria, which has nearly doubled in 10 years (2004-2014). Different from ß-globin gene variations, no increasing trend in α defects was observed in our study cohort. Consistently, 58.0% of patients have an Italian origin, suggesting no broad influence of foreign migration in the α-globin genes genetic background. As few defects are prevalent in each country of origin or ethnic group, their knowledge may provide a proper strategy for the identification of mutations in immigrant individuals in a non-endemic region and be important for carrier identification and prenatal screening.
