Alpha-thalassemia is highly prevalent in the plural society of Brazil and is a public health problem. There is limited knowledge on its accurate frequency and distribution in the Amazon region. Knowing the frequency of thalassemia and the prevalence of responsible mutations is, therefore, an important step in the understanding and control program. Hematological and molecular data, in addition to serum iron and serum ferritin, from 989 unrelated first-time blood donors from Amazonas Hemotherapy and Hematology Foundation (FHEMOAM) were collected. In this study, the subjects were screened for −α3.7/4.2/20.5, −SEA, −FIL, and −MED deletions. Alpha-thalassemia screening was carried out between 2016 and 2017 among 714 (72.1%) male and 275 (27.9%) female donors. The aims of this analysis were to describe the distribution of various alpha-thalassemia alleles by gender, along with their genotypic interactions, and to illustrate the hematological changes associated with each phenotype. Amongst the patients, 5.35% (n = 53) were diagnosed with deletion –α−3.7 and only one donor with α−4.2 deletion. From the individuals with –α−3.7, 85.8% (n = 46) were heterozygous and 14.20% (n = 7) were homozygous. The frequency of the –α−3.7 deletion was higher in male (5.89%) than in female (4.0%). There is no significant difference in the distribution of –α−3.7 by gender (p=0.217). The –α20.5, −SEA, and −MED deletions were not found. All subjects were analyzed for serum iron and serum ferritin, with 1.04% being iron deficient (n = 5) and none with very high levels of stored iron (>220 µg/dL). Alpha-thalassemia-23.7kb deletion was the most common allele detected in Manaus blood donors, which is a consistent result, once it is the most common type of α-thalassemia found throughout the world. As expected, the mean of hematological data was significantly lower in alpha-thalassemia carriers (p<0.001), mainly homozygous genotype. Leukocytes and platelet count did not differ significantly. Due to the small number of individuals with iron deficiency found among blood donors, the differential diagnosis between the two types of anemia was not possible, even because minor changes were found among hematological parameters with iron deficiency and α-thalassemia. Despite this, the study showed the values of hematological parameters, especially MCV and MCH, are lower in donors with iron deficiency, especially when associated with α-thalassemia, and therefore, it may be useful to discriminate different types of microcytic anaemia. In conclusion, we believed screening for thalassemia trait should be included as part of a standard blood testing before blood donation. It should be noted that this was the first study to perform the screening for alpha deletions in blood donors from the Manaus region, and further studies are required to look at the effects of donated thalassemic blood.
Background Over a third of the world’s population is at risk of Plasmodium vivax-induced malaria. The unique aspect of the parasite’s biology and interactions with the human host make it harder to control and eliminate the disease. Glucose-6-phosphate dehydrogenase (G6PD) deficiency and Duffy-negative blood groups are two red blood cell (RBC) variations that can confer protection against malaria. Methods Molecular genotyping of G6PD and Duffy variants was performed in 225 unrelated patients (97 with uncomplicated and 128 with severe vivax malaria) recruited at a Reference Centre for Infectious Diseases in Manaus. G6PD and Duffy variants characterizations were performed using Real Time PCR (qPCR) and PCR–RFLP, respectively. Results The Duffy blood group system showed a phenotypic distribution Fy(a + b−) of 70 (31.1%), Fy(a + b +) 96 (42.7%), Fy(a−b +) 56 (24.9%) and Fy(a−b−) 1 (0.44%.) The genotype FY*A/FY*B was predominant in both uncomplicated (45.3%) and severe malaria (39.2%). Only one Duffy phenotype Fy(a-b) was found and this involved uncomplicated vivax malaria. The G6PD c.202G > A variant was found in 11 (4.88%) females and 18 (8.0%) males, while c.376A > G was found in 20 females (8.88%) and 23 (10.22%) male patients. When combined GATA mutated and c.202G > A and c.376A > G mutated, was observed at a lower frequency in uncomplicated (3.7%) in comparison to severe malaria (37.9%). The phenotype Fy(a−b +) (p = 0.022) with FY*B/FY*B (p = 0.015) genotype correlated with higher parasitaemia. Conclusions A high prevalence of G6PD c202G > A and c.376A > G and Duffy variants is observed in Manaus, an endemic area for vivax malaria. In addition, this study reports for the first time the Duffy null phenotype Fy(a-b-) in the population of the Amazonas state. Moreover, it is understood that the relationship between G6PD and Duffy variants can modify clinical symptoms in malaria caused by P. vivax and this deserves to be further investigated and explored among this population.
Background: Alpha Thalassemia (a-thal) is a heterogeneous group of hereditary alterations caused by deletions that affect alpha regulatory genes and the 3.7Kb deletion is the most frequent worldwide. In Brazil, the prevalence ranges from 20% and 35%, depending mainly on race, being more predominant in Afro-descendants. Purpose: The aim was to determine ?-thal -?3.7Kb and -?4.2Kb deletions, estimating their frequency in individuals from five regions of Amazon. Methods: Volunteers (individuals >18 years old, of both genders) blood samples (n=1809) were collected from march 2014 to september 2017, at hospitals and/or health centers of each participant city. Alpha Thalassemia 3.7Kb genotyping was performed by GAP-PCR, while 4.2Kb deletion by Multiplex-PCR. The studied population included: Manaus (capital), 356 (19.7%) samples; Iranduba 232 (12.8%); Manacapuru, 287 (15.9%); Presidente Figueiredo, 370 (20.5%); Itacoatiara, 301 (16.6%); and Coari, 263 (14.5%). Results: The average age among males was 35.3±14.8, while for females it was 36.7±14.9 years old. Alpha Thalassemia was diagnosed in 143 individuals (7.9%) and all of these individuals carried the 3.7Kb deletion, 5.95% in heterozygosis and 1.95% in homozygosis. The associations analyses to the a-thal genotypes were statistically significant for all hematological parameters (p<.001), except serum iron and serum ferritin analyses among carriers ?-thal. Microcytosis (MCV <80fL) was found in 158 individuals (8,46%). Conclusion: The alfa-thal prevalence corroborates with other Brazilians studies. Molecular diagnosis is important to prevent the most severe forms of the disease, thus epidemiological studies using molecular tools become extremely important in regions where the disease is underestimated. In this context, this is the first study that reports ?-thalassemia deletion in the population from State of Amazonas. Our findings are relevant because they have impact in the clinical therapeutic choice and also demonstrate the importance of differential diagnosis between genetic anemia and iron deficiency anemia.
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