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We have evaluated the mutation profile in a sample of 127 unrelated beta-thalassemia (beta thal) individuals, diagnosed through A2 and fetal hemoglobin quantification by high-performance liquid chromatography (HPLC) from the Brazilian southernmost state, where a flow of Italian immigrants had occurred in the late 19th century, mainly from Northern Italy. The molecular analysis was performed by DNA sequencing of the most common mutations found in the Mediterranean region. The beta 0 codon 39 nonsense mutation was the most frequent alteration (50.9%), followed by beta+ IVSI 110 G>A (18.1%), beta 0 IVSI 1 G>A (12.9%), beta+ IVSI 6 T>C (9.5%), and other rare mutations (8.6%). The chosen gene sequence was able to identify 91% beta-thal mutations in the population studied, showing some similarity with allele frequencies of the mainly colonizing countries of Rio Grande do Sul state. The comparison of our results to other Brazilian studies has shown significant differences. Therefore, we can conclude that the genotypic profile of beta-thal shows great variability. Hence, it would be arbitrary to infer regional study results as being representative of the Brazilian whole population. Brazilian researchers of different regions should identify their most frequent genotypes to provide better understanding on this disease and state adequate public health policies.

Objective: alpha-Hemoglobin stabilizing protein (AHSP) binds alpha-hemoglobin (Hb), avoiding its precipitation and its pro-oxidant activity. In the presence of betaHb, the alphaHb-AHSP complex is dismembered and betaHb displaces AHSP to generate the quaternary structure of Hb. The relationship between Hb formation and alterations in AHSP expression, which may affect human erythropoiesis, has not yet been described in human cells. Hence, in this study, we examined the effects of AHSP knockdown in hemin-induced K562 and erythropoietin-induced CD34(+) cells with particular reference to cellular aspects and gene expression., Materials and Methods: Short-hairpin RNA expression vectors aimed at the AHSP mRNA target sequence were cloned and transfected into K562 and CD34(+) cells. K562 and CD34(+) cells were stimulated to erythroid differentiation. Cells were examined in terms of gene expression using quantitative real-time polymerase chain reaction; reactive oxygen species (ROS) production, apoptosis, and Hb production through flow cytometry assays; and immunofluorescence assays for globin chains., Results: RNA interference-mediated knockdown of AHSP expression resulted in considerable alphaHb precipitation, as well as in a significant decrease in HbF formation. AHSP-knockdown cells demonstrated an increased ROS production and increased rate of apoptosis., Conclusion: These findings strengthen the hypothesis that AHSP stabilizes the alphaHb chain, avoiding its precipitation and its ability to generate ROS, which implicate in cell death. Moreover, data indicate that AHSP may be highly significant for human hemoglobin formation and suggest that AHSP is a key chaperone protein during human erythropoiesis.