Thalassemia, a human blood disorder / Talassemia, uma doença do sangue humano

A group of inherited blood defects is known as Thalassemia is among the world's most prevalent hemoglobinopathies. Thalassemias are of two types such as Alpha and Beta Thalassemia. The cause of these defects is gene mutations leading to low levels and/or malfunctioning α and β globin proteins, respectively. In some cases, one of these proteins may be completely absent. α and β globin chains form a globin fold or pocket for heme (Fe++) attachment to carry oxygen. Genes for alpha and beta-globin proteins are present in the form of a cluster on chromosome 16 and 11, respectively. Different globin genes are used at different stages in the life course. During embryonic and fetal developmental stages, γ globin proteins partner with α globin and are later replaced by β globin protein. Globin chain imbalances result in hemolysis and impede erythropoiesis. Individuals showing mild symptoms include carriers of alpha thalassemia or the people bearing alpha or beta-thalassemia trait. Alpha thalassemia causes conditions like hemolytic anemia or fatal hydrops fetalis depending upon the severity of the disease. Beta thalassemia major results in hemolytic anemia, growth retardation, and skeletal aberrations in early childhood. Children affected by this disorder need regular blood transfusions throughout their lives. Patients that depend on blood transfusion usually develop iron overload that causes other complications in the body systems like renal or hepatic impairment therefore, thalassemias are now categorized as a syndrome. The only cure for Thalassemias would be a bone marrow transplant, or gene therapy with currently no significant success rate. A thorough understanding of the molecular basis of this syndrome may provide novel insights and ideas for its treatment, as scientists have still been unable to find a permanent cure for this deadly disease after more than 87 years since it is first described in 1925.

Um grupo de defeitos sanguíneos hereditários é conhecido como talassemia e está entre as hemoglobinopatias mais prevalentes do mundo. As talassemias são de dois tipos, como talassemia alfa e beta. As causas desses defeitos são as mutações genéticas que levam a níveis baixos e/ou proteínas de globina com mau funcionamento, respectivamente. Em alguns casos, uma dessas proteínas pode estar completamente ausente. As cadeias de globina α e β formam uma dobra ou bolsa de globina para a fixação de heme (Fe ++) para transportar oxigênio. Os genes das proteínas alfa e beta globina estão presentes na forma de um cluster nos cromossomos 16 e 11, respectivamente. Diferentes genes de globina são usados em diferentes estágios do curso de vida. Durante os estágios de desenvolvimento embrionário e fetal, as proteínas γ globina se associam à α globina e, posteriormente, são substituídas pela proteína β globina. Os desequilíbrios da cadeia de globina resultam em hemólise e impedem a eritropoiese. Indivíduos que apresentam sintomas leves incluem portadores de talassemia alfa ou as pessoas com traços de talassemia alfa ou beta. A talassemia alfa causa condições como anemia hemolítica ou hidropsia fetal fatal, dependendo da gravidade da doença. A beta talassemia principal resulta em anemia hemolítica, retardo de crescimento e aberrações esqueléticas na primeira infância. As crianças afetadas por esse distúrbio precisam de transfusões de sangue regulares ao longo da vida. Os pacientes que dependem de transfusão de sangue geralmente desenvolvem sobrecarga de ferro que causa outras complicações nos sistemas do corpo, como insuficiência renal ou hepática, portanto as talassemias agora são classificadas como uma síndrome. A única cura para as talassemias seria um transplante de medula óssea ou terapia genética sem atualmente uma taxa de sucesso significativa. Uma compreensão completa da base molecular dessa síndrome pode fornecer novos insights e ideias para seu tratamento, [...].

Enfermedad por hemoglobina H: primer caso de dobles heterocigotos hemoglobina Constant Spring / Sudeste Asiático en Costa Rica / Hemoglobin H disease: first case of double heterozygous hemoglobin Constant Spring / Southeast Asian in Costa Rica

Resumen La enfermedad por hemoglobina H es un cuadro clínico que se presenta en las alfa talasemias, las cuales son enfermedades que cursan con anemia microcítica hipocrómica, debidas principalmente a deleciones en el gen de alfaglobina, lo que disminuye la producción de la cadena de alfa globina y promueve la formación de variantes de hemoglobina. Cuando se detectan variantes de hemoglobina en las alfa talasemias, por lo general, se debe a genotipos homocigotas o dobles heterocigotas para mutaciones y deleciones del gen de alfa globina coheredadas. En este artículo se describe el primer caso en Costa Rica, de dos hermanos con enfermedad por hemoglobina H, que fenotípicamente presentaron las variantes de hemoglobina H y hemoglobina Constant Spring en el análisis electroforético de la hemoglobina, y cuyo análisis molecular del gen de alfa globina detectó tanto la deleción sudeste asiático como la mutación para hemoglobina Constant Spring, siendo diagnosticados como dobles heterocigotos por alfa talasemia (genotipo --SEA/ααCS).

Abstract Hemoglobin H disease occurs in patients with alpha thalassemia, diseases associated with hypochromic microcytic anemia, mainly due to deletions in the alpha globin gene, which decreases the production of the alpha globin chain and promotes the formation of hemoglobin variants. When hemoglobin variants are detected in alpha thalassemias it is usually due to homozygoys or doublé heterozygous genotypes, for mutations and deletions of the alpha globin gene. This article describes the first case in Costa Rica of two siblings with hemoglobin H disease, who phenotypically presented the hemoglobin H and Constant Spring hemoglobin variants in the electrophoretic analysis of the hemoglobin, and whose molecular DNA analysis of the alpha globin gene detected both, the Southeast Asian deletion and the mutation for Constant Spring Hemoglobin, being diagnosed as compound heterozygous for alpha thalassemia (genotipe --SEA/ααCS).

Herencia conjunta de α+-talasemia y portador de hemoglobina S / Co-inheritance of α+-thalassemia and sickle trait

Resumen En este reporte de caso se describe el primer paciente doble heterocigoto para alfa+-talasemia tipo -3,7 y rasgo heterocigoto por hemoglobina S en Costa Rica, diagnosticado desde su nacimiento por medio del tamizaje neonatal como heterocigoto para hemoglobina S. Luego de la detección de la hemoglobina S por tamizaje, el paciente fue referido al servicio de Hematología del Hospital Nacional de Niños para su seguimiento, en donde se observa hemograma con índices y morfología de glóbulos rojos sugestivos de alfa talasemia, con presentación de electroforesis de hemoglobina con patrón AS cuya expresión relativa de HbS era menor de lo esperado, lo que motivó a efectuar estudio molecular del gen de alfa globina, que confirmó el diagnóstico de alfa talasemia con deleción heterocigota de tipo -3,7 en herencia conjunta con la heterocigosis de hemoglobina S.

Abstract In this case report we describe the first patient compound heterozygous for type -3.7 alpha+ thalassemia and sickle cell trait in Costa Rica, who was diagnosed from birth by neonatal screening as heterozygous for hemoglobin S. After detection of hemoglobin S by screening, the patient was referred to the Hematology service of the National Children`s Hospital for follow-up, where hemogram with indexes and morphology of red blood cells suggestive of alpha thalassemia is observed, presenting hemoglobin electrophoresis with AS pattern whose relative expression of hemoglobin S was lower tan expected, which led to a molecular study of the alpha globin gene confirming the diagnosis of alpha thalassemia with heretozygous deletion of type -3.7, in co-inheritance with hemoglobin S heterozygosis.

Estudo da associação entre talassemia alfa e doença falciforme em pacientes do hemocentro regional de Montes Claros / Study of the association between alpha thalassemia and falciform disease in patiensts of the hemocentro regional de Montes Claros

OBJETIVO: Avaliar a coexistência da talassemia alfa (a-Tal) e sua interferência no curso clínico dos pacientes com Doença Falciforme no Hemocentro Regional de Montes Claros-MG. Metodologia: Estudo transversal analítico, com amostra aleatorizada, na qual foram incluídos pacientes triados pelo Programa Estadual de Triagem Neonatal de Minas Gerais e encaminhadas ao Hemocentro Regional de Montes Claros, com perfil eletroforético compatível com anemia falciforme, nascidos no período entre 26/01/2000 e 13/05/2014. Os dados clínicos dos pacientes foram coletados nos prontuários médicos do Ambulatório do Hemocentro Regional de Montes Claros. A genotipagem de a-Tal foi realizada por PCR multiplex (alelos: -a3.7; -a4.2; --SEA; --FIL; --MED; -(a) 20.5 e --THAI) no Serviço de Pesquisa Serviço de Pesquisa da Fundação Hemominas. Os dados foram analisados em teste estatísticos qui-quadrado em Software SPSS versão 16.0. Resultados: Foram estudados 50 pacientes, sendo 25 (50%) do sexo masculino e 25 (50%) do sexo feminino. A idade dos pacientes variou de 9 meses a 15 anos de idade. A prevalência da a-Tal foi de 30%. Não houve associação estatística significativa entre a presença de a-Tal e infecção, internação, crises álgicas, sequestro esplênico, esplenectomia, transfusão sanguínea e Acidente Vascular Cerebral (AVC). No entanto, a frequência de crises álgicas, esplenectomia e AVC foi menor nos pacientes que apresentavam coexistência da a-Tal. Conclusões: A prevalência de a-Tal em indivíduos com anemia falciforme no nosso estudo foi 30%. Algumas manifestações graves da AF ocorreram de forma menos frequente nos pacientes com a interação da a-Tal/anemia falciforme. (AU)

Objective: To evaluate the coexistence of alpha thalassemia (a-Tal) and its interference in the clinical course of patients with sickle cell disease at Hemocentro Regional de Montes Claros-MG. Methodology: This is a cross-sectional, analytical study with a randomized sample carried out with patients screened by the State Neonatal Screening Program of Minas Gerais and referred to the Hemocentro Regional de Montes Claros with an electrophoretic profile compatible with sickle cell anemia, born between 01.26.2000 and 05.13.2014. The clinical data of the patients were collected in the medical records of the Outpatient Clinic of the Hemocentro Regional de Montes Claros. The a-Tal genotyping was performed by multiplex PCR (alleles: -a3.7; -a4.2; --SEA; --FIL; --MED; - (a) 20.5 and --THAI) in the Research Service Fundação Hemominas. The data were analyzed in chi-square statistical test in SPSS Software version 16.0. Results: Fifty patients were studied, 25 (50%) were male, and 25 (50%) were female. Patients´ ages ranged from 9 months to 15 years old. The prevalence of a-Tal was 30%. There was no significant statistical association between the presence of a-Tal and infection, hospitalization, painful crises, splenic sequestration, splenectomy, blood transfusion and cerebrovascular accident (CVA). However, the frequency of painful seizures, splenectomy and CVA was lower in patients with a-Tal coexistence. Conclusions: The prevalence of a-Tal in individuals with sickle cell anemia in our study was 30%. Some severe manifestations of SCA occurred less frequently in patients with a-Tal/sickle cell anemia interaction. (AU)

Talasemias: Aspectos clínicos / Thalassemias: Clinical aspects / Talassemias: Aspectos clínicos

Los síndromes talasémicos, junto con las hemoglobinopatías talasémicas, las hemoglobinopatías estructurales y los síndromes de sobreexpresión representan las diferentes formas clínicas de las hemoglobinopatías. Los defectos genéticos responsables de los síndromes talasémicos determinan la síntesis disminuída o nula de la cadena de globina correspondiente. Según la cadena cuya síntesis es defectuosa, los síndromes talasémicos se clasifican en a-talasemias, b-talasemias, etc. Según las diferentes combinaciones de fenotipos particulares, las a-talasemias se clasifican en silente, portador, enfermedad con hemoglobina H e hidropesía fetal, y las b-talasemias en menor, intermedia y mayor. La sospecha diagnóstica de los síndromes talasémicos leves y de las hemoglobinopatías talasémicas es fácil a partir de la anemia leve con marcada microcitosis hipocrómica, ausencia indudable de ferropenia y cuadro familiar positivo. La electroforesis de hemoglobina con una cuantificación de hemoglobina A2 mayor de 3,5% prácticamente confirma el diagnóstico de una b-talasemia menor, mientras que una hemoglobina A2 normal o disminuida va a hacer sospechar una a-talasemia leve cuyo diagnóstico debe ser confirmado por estudio de ADN. Una vez establecida la condición talasémica del propósito es imprescindible identificar qué familiares consanguíneos son o no portadores del mismo gen talasémico, y estudiar a los cónyuges de los talasémicos detectados, a fin de prever, a través del consejo genético, el nacimiento de hijos homocigotas o doble heterocigotas con formas más severas de talasemias o hemoglobinopatías.

Thalassemic syndromes, together with thalassemic hemoglobinopathies, structural hemoglobinopathies and over-expression syndromes represent the different clinical presentations of hemoglobinopathies, which are the mutational or deletional defects of globin genes. Genetic defects responsible for thalassemic syndromes determine a reduced or a lack of synthesis of the related chain. According to the defective synthesized chain, thalassemias are classified into a-thalassemias, b-thalassemias, etc. Depending on the different combinations of two or more phenotypes, a-thalassemias are classified into silent, carrier, Hb H disease and fetal hydrops, while b-thalassemias are classified into minor, intermediate and major b-thalassemia. Diagnostic suspicion of mild thalassemic syndromes and thalassemic hemoglobinopathies is easy based on a mild anemia with pronounced microcytosis and hypochromia, unquestionable absence of iron deficiency and positive family background. Hemoglobin electrophoresis with A2 hemoglobin level higher than 3.5% almost confirms a b-thalassemia minor, while a low or normal A2 hemoglobin level makes mild a-thalassemia suspicious and diagnosis must be confirmed by DNA study. Once the thalassemic condition of the propositus is confirmed, it is essential to identify which consanguineous relatives are or are not carriers of the same thalassemic gene, and then to study the couples of all already identified thalassemic relatives, in order to forecast, through genetic counselling, the birth of homozygous or double heterozygous children with more severe thalassemic or hemoglobinopathic conditions.

As síndromes talassêmicas, junto com as hemoglobinopatias talassêmicas, as hemoglobinopatias estruturais e as síndromes de sobre-expressão representam as diferentes formas clínicas das hemoglobinopatias. Os defeitos genéticos responsáveis pelas síndromes talassêmicas determinam a síntese diminuída ou nula da cadeia de globina correspondente. Segundo a cadeia cuja síntese é defeituosa, as síndromes talassêmicas são classificadas em a-talassemias, b-talassemias, etc. Conforme as diferentes combinações de fenótipos particulares, as a-talassemias são classificadas em silente, portador, doença com hemoglobina H e hidropesia fetal, e as b-talassemias em menor, intermediária e maior. A suspeita diagnóstica das síndromes talassêmicas leves e das hemoglobinopatias talassêmicas é fácil a partir da anemia leve com marcada microcitose hipocrômica, ausência induvidável de ferropenia e quadro familiar positivo. A eletroforese de hemoglobina com uma quantificação de hemoglobina A2 maior de 3,5% praticamente confirma o diagnóstico de uma b-talassemia menor, ao passo que uma hemoglobina A2 normal ou diminuída vai fazer suspeitar uma a-talassemia leve cujo diagnóstico deve ser confirmado por estudo de DNA. Assim que é estabelecida a condição talassêmica do propósito, é imprescindível identificar quais são os familiares consanguíneos e quais não são portadores do mesmo gene talassêmico, e estudar os cônjuges dos talassêmicos detectados, visando a prever, através do conselho genético, o nascimento de filhos homozigotas ou duplo-heterozigotas com formas mais severas de talassemias ou hemoglobinopatias.

Genetic determinants and stroke in children with sickle cell disease / Determinantes genéticos e Acidente Vascular Encefálico em crianças com doença falciforme

Abstract Objective: To verify genetic determinants associated with stroke in children with sickle cell disease (SCD). Methods: Prospective cohort with 110 children submitted to neonatal screening by the Neonatal Screening Program, between 1998 and 2007, with SCD diagnosis, followed at a regional reference public service for hemoglobinopathies. The analyzed variables were type of hemoglobinopathy, gender, coexistence with alpha thalassemia (α-thal), haplotypes of the beta globin chain cluster, and stroke. The final analysis was conducted with 66 children with sickle cell anemia (SCA), using the chi-squared test in the program SPSS® version 14.0. Results: Among children with SCD, 60% had SCA. The prevalence of coexistence with α-thal was 30.3% and the Bantu haplotype (CAR) was identified in 89.2%. The incidence of stroke was significantly higher in those with SCA (27.3% vs. 2.3%; p = 0.001) and males (24.1% vs. 9.6%; p = 0.044). The presence of α-thal (p = 0.196), the CAR haplotype (p = 0.543), and socioeconomic factors were not statistically significant in association with the occurrence of stroke. Conclusion: There is a high incidence of stroke in male children and in children with SCA. Coexistence with α-thal and haplotypes of the beta globin chain cluster did not show any significant association with stroke. The heterogeneity between previously evaluated populations, the non-reproducibility between studies, and the need to identify factors associated with stroke in patients with SCA indicate the necessity of conducting further research to demonstrate the relevance of genetic factors in stroke related to SCD.

Resumo Objetivo: Verificar fatores genéticos associados ao acidente vascular encefálico (AVE) em crianças com doença falciforme (DF). Métodos: Coorte prospectiva de 110 crianças submetidas à triagem neonatal pelo Programa de Triagem Neonatal, entre 1998-2007, com o diagnóstico de DF, atendidas em serviço público regional de referência em hemoglobinopatias. As variáveis analisadas foram: tipo de hemoglobinopatia, sexo, coexistência da alfa-Talassemia (α-Tal), haplótipos do cluster da cadeia beta globina e AVE. A análise estatística final foi feita com 66 crianças com anemia falciforme, por meio do teste do qui-quadrado no programa SPSS® 14.0. Resultados: Entre as crianças com DF, 60% eram portadoras de anemia falciforme. A prevalência da coexistência com a α-Tal foi de 30,3% e o haplótipo Bantu (CAR) foi identificado em 89,2%. A incidência de AVE foi significativamente maior nas crianças com AF (27,3% versus 2,3%; p = 0,001) e no sexo masculino (24,1% versus 9,6%; p = 0,044. A presença da α-Tal (p = 0,196), do haplótipo CAR (p = 0,543) e de fatores socioeconômicos não foi significantemente associada à ocorrência de AVE. Conclusão: O AVE apresenta alta incidência em crianças com AF e em crianças do sexo masculino. Coexistência de α-Tal ou de haplótipos do cluster da betaglobina não apresentaram associação significante com AVE. A heterogeneticidade entre as populações previamente avaliadas e a não reprodutibilidade entre estudos indicam a necessidade de novas pesquisas para verificar o papel desses fatores genéticos no AVE em crianças com DF.

Hemoglobin A2 values in sickle cell disease patients quantified by high performance liquid chromatography and the influence of alpha thalassemia

BACKGROUND: In sickle cell disease, the quantification of Hb A2 is important for the differential diagnosis between sickle cell anemia (Hb SS) and Hb S/ß0-thalassemia.OBJECTIVE: To determine Hb A2 levels as quantified by high performance liquid chromatography in patients with sickle cell anemia (Hb SS) and with the SC hemoglobinopathy, with or without concomitant alpha thalassemia.METHODS: This is a retrospective study of 242 children aged between two and six years with diagnoses of Hb SS or Hb SC. The hemoglobin was evaluated using high performance liquid chromatography and alpha thalassemia [3.7 kb deletion (-a3.7)] was detected by polymerase chain reaction. Patients were classified as homozygous (-a3.7/-a3.7), heterozygous (-a3.7/a), or homozygous wild-type. Analysis of variance was used to compare the mean Hb A2 values between the alpha thalassemia groups.RESULTS: The mean (± standard deviation) Hb A2 concentrations in the Hb SS group (n = 135) was 3.68 ± 0.65%. The mean values for individuals with Hb SS and heterozygous (n = 28) or homozygous for alpha thalassemia (n = 3) were 3.98 ± 0.64% and 4.73 ± 0.25%, respectively. The mean Hb A2 of all the Hb SC patients (n = 107) was 4.01 ± 0.507 with 4.29 ± 0.41% and 4.91 ± 0.22% in individuals heterozygous (n = 23) and homozygous for alpha thalassemia (n = 7), respectively. All patients homozygous for alpha thalassemia had Hb A2 levels above 3.5%. However, Hb A2 values above 5.2% were seen in patients with Hb SS and Hb SC, independently of alpha thalassemia.CONCLUSION: Hb A2 levels are elevated in patients with Hb S or Hb C, and are directly influenced by the alpha thalassemia genotypes.

Bases moleculares de alfa-talasemia en la Argentina

La α-talasemia, es uno de los desórdenes hereditarios más frecuentes mundialmente. Al presente, el diagnóstico molecular es la única herramienta que permite el diagnóstico certero. El propósito de este trabajo fue caracterizar las bases moleculares de estos síndromes en nuestro medio, y establecer relaciones genotipo-fenotipo. Mediante la complementación de distintas técnicas de biología molecular e hibridación fluorescente in situ (FISH), se logró poner en evidencia la presencia de mutaciones α-talasémicas en 145 de 184 (78.8%) pacientes estudiados con perfil hematológico compatible con α-talasemia. Dentro de este grupo, las deleciones correspondieron al defecto genético más frecuente, prevaleciendo la mutación -α3.7 en genotipos heterocigotas y homocigotas. Asimismo, en pacientes con fenotipo α0 las deleciones prevalentes fueron -MED y -CAL/CAMP. Este estudio permitió también describir una deleción de la región sub-telomérica en un paciente con α-talasemia y retraso mental. En el 7.6% de los pacientes caracterizados clínicamente como posibles α-talasémicos (microcitosis con valores de Hb A2 inferiores al 3.5%), se hallaron mutaciones β-talasémicas en estado heterocigota. Se lograron establecer perfiles hematológicos asociados a los genotipos α+ y α0 para pacientes adultos y niños. Esperamos que este trabajo pueda servir como guía para reconocer posibles portadores α-talasémicos. También permite destacar el trabajo en conjunto de médicos hematólogos, el laboratorio (bioquímico y de biología molecular) y de los médicos genetistas, con el fin de proporcionar adecuado consejo genético.

The α-thalassemia is one of the most common hereditary disorders worldwide. Currently, molecular diagnostics is the only available tool to achieve an accurate diagnosis. The purpose of this study was to characterize the molecular bases of these syndromes in our environment and to establish genotype-phenotype associations. Through a combination of different molecular techniques and fluorescent in situ hybridization (FISH),we were able to find α-thalassemic mutations in 145 of the 184 patients (78.8%) studied with hematological parameters compatible with α-thalassemia. Deletions of the a-globin genes resulted the major molecular cause of the disease, and the most frequent mutation was -α3.7, found in homozygous and heterozygous genotypes. In patients with α0 phenotypes, other prevalent mutations were -MED and -CAL/CAMP. The description of a sub-telomeric deletion in a patient with α-thalassemia and mental retardation was also achieved. β-thalassemic mutations in heterozygous state were found in 7.6% of the patients, who presented α-thalassemic clinical features (microcytosis and Hb A2 levels below 3.5%). Hematologic profiles for the α+ and α0 genotypes were established for adult and pediatric patients. Hopefully, this work will provide guidelines for the detection of possible α-thalassemic carriers. It also highlights the collaborative work of hematologists, the biochemical and molecular biology laboratory and genetists, in order to provide appropriate genetic counseling.

Investigating alpha-globin structural variants: a retrospective review of 135000 Brazilian individuals

Background: Brazil has a multiethnic population with a high diversity of hemoglobinopathies. While screenings for beta-globin mutations are far more common, alterations affecting alpha-globin genes are usually more silent and less well known. The aim of this study was to describe the results of a screening program for alpha-globin gene mutations in a representative sample of the Southeastern Brazilian population. Methods: A total of 135,000 individuals, including patients with clinical suspicion of hemoglobinopathies and their family members, randomly chosen individuals submitted to blood tests and blood donors who were abnormal hemoglobin carriers were analyzed. The variants were screened by alkaline and acid electrophoreses, isoelectric focusing and cation-exchange high performance liquid chromatography (HPLC) and the abnormal chains were investigated by reverse-phase high performance liquid chromatography (RP-HPLC). Mutations were identified by molecular analyses, and the oxygen affinity, heme-heme cooperativity and Bohr effect of the variants were evaluated by functional tests. Results: Four new and 22 rare variants were detected in 98 families. Some of these variants were found in co-inheritance with other hemoglobinopathies. Of the rare hemoglobins, Hasharon, Stanleyville II and J-Rovigo were the most common, the first two being S-like and associated with alpha-thalassemia. Conclusion: The variability of alpha-globin alterations reflects the high degree of racial miscegenation and an intense internal migratory flow between different Brazilian regions. This diversity highlights the importance of programs for diagnosing hemoglobinopathies and preventing combinations that may lead to important clinical manifestations in multiethnic populations.

Survival and mortality among users and non-users of hydroxyurea with sickle cell disease / Sobrevida e mortalidade em usuários e não usuários de hidroxiureia com doença falciforme / Sobrevida y mortalidad en usuarios y no usuarios de hidroxiurea con enfermedad falciforme

OBJECTIVE: to estimate survival, mortality and cause of death among users or not of hydroxyurea with sickle cell disease. METHOD: cohort study with retrospective data collection, from 1980 to 2010 of patients receiving inpatient treatment in two Brazilian public hospitals. The survival probability was determined using the Kaplan-Meier estimator, survival calculations (SPSS version 10.0), comparison between survival curves, using the log rank method. The level of significance was p=0.05. RESULTS: of 63 patients, 87% had sickle cell anemia, with 39 using hydroxyurea, with a mean time of use of the drug of 20.0±10.0 years and a mean dose of 17.37±5.4 to 20.94±7.2 mg/kg/day, raising the fetal hemoglobin. In the comparison between those using hydroxyurea and those not, the survival curve was greater among the users (p=0.014). A total of 10 deaths occurred, with a mean age of 28.1 years old, and with Acute Respiratory Failure as the main cause. CONCLUSION: the survival curve is greater among the users of hydroxyurea. The results indicate the importance of the nurse incorporating therapeutic advances of hydroxyurea in her care actions. .

OBJETIVO: estimar a sobrevida, mortalidade e causa de morte em usuários ou não de hidroxiureia com doença falciforme. MÉTODO: coorte retrospectiva de 1980 a 2010, de pacientes internados em dois hospitais públicos brasileiros. Determinou-se a probabilidade de sobrevida com Kaplan-Meier, cálculos de sobrevida (SPSS versão 10.0), comparação entre curvas de sobrevida e método Log Rank. Nível de significância p=0,05. RESULTADOS: de 63 pacientes, 87% estavam com anemia falciforme, sendo 39 em uso de hidroxiureia, com média de idade na instituição do fármaco de 20,0±10,0 anos e dosagem média de 17,37±5,4 a 20,94±7,2mg/kg/dia, elevando a hemoglobina fetal. Na comparação de usuários e não usuários de hidroxiureia, a curva de sobrevida foi maior nos usuários (p=0,014). Ocorreram 10 óbitos, com idade média de 28,1 anos, tendo como causa principal a Insuficiência Respiratória Aguda. CONCLUSÃO: a curva de sobrevida é maior nos usuários de hidroxiureia. Os resultados apontam a importância do enfermeiro incorporar avanços terapêuticos da hidroxiureia em suas ações assistenciais. .

OBJETIVO: estimar la sobrevida, la mortalidad y la causa de muerte de usuarios y no usuarios de hidroxiurea con enfermedad falciforme. MÉTODO: cohorte retrospectiva de 1980 a 2010 de pacientes internados en dos hospitales públicos brasileños. Se determinó la probabilidad de sobrevida con Kaplan-Meier, cálculos de sobrevida (SPSS versión 10.0), comparación entre curvas de sobrevida, método Log Rank. Nivel de significado p=0,05. RESULTADOS: de 63 pacientes, 87% estaban con anemia falciforme, siendo que 39 usaban hidroxiurea, promedio de edad en la institución del fármaco de 20,0±10,0 años y dosificación promedio de 17,37±5,4 a 20,94±7,2mg/kg/día, elevando la hemoglobina fetal. En la comparación de usuarios y no usuarios de hidroxiurea, la curva de sobrevida fue mayor en los usuarios (p=0,014). Ocurrieron 10 muertes, edad promedio de 28,1 años, siendo la Insuficiencia Respiratoria Aguda la causa principal. CONCLUSIÓN: la curva de sobrevida es mayor en los usuarios de hidroxiurea. Los resultados apuntan la importancia de que el enfermero incorpore los avances terapéuticos de la hidroxiurea en sus acciones asistenciales. .

Alfa-Talassemias: aspectos moleculares e diagnóstico / Alpha-Thalassemias: molecular aspects and diagnosis

A α-talassemia é um dos distúrbios da síntese de hemoglobina mais comuns no mundo, sendo causada, principalmente,por mutações delecionais nos genes α-globínicos. De acordo com o número degenes mutados que varia de um a quatro, a α-talassemia pode ser divididaem quatro fenótipos: α-talassemia silenciosa, traço α-talassêmico, Doençade HbH e hidropsia fetal, espectivamente. Segundo a literatura, afrequência de α-talassemia no Brasil também é considerável, sendo de grande importância o diagnósticocorreto deste distúrbio, que pode ser realizado com auxílio de exames convencionais que apresentam vantagens e desvantagens. Contudo, em alguns casos, principalmente nas formas menores da α-talassemia, a confirmação diagnóstica só pode ser realizada através dos exames moleculares que, apesar de confirmatórios, não estão disponíveisem grande parte dos laboratórios de análises clínicas e, devido ao custo, não são acessíveis à população em geral..

Molecular analysis and association with clinical and laboratory manifestations in children with sickle cell anemia

Objectives: To analyze the frequency of βS-globin haplotypes and alpha-thalassemia, and their influence on clinical manifestations and the hematological profile of children with sickle cell anemia. Method: The frequency of βS-globin haplotypes and alpha-thalassemia and any association with clinical and laboratorial manifestations were determined in 117 sickle cell anemia children aged 3–71 months. The confirmation of hemoglobin SS and determination of the haplotypes were achieved by polymerase chain reaction-restriction fragment length polymorphism, and alpha-thalassemia genotyping was by multiplex polymerase chain reaction (single-tube multiplex-polymerase chain reaction). Results: The genotype distribution of haplotypes was 43 (36.7%) Central African Republic/Benin, 41 (35.0%) Central African Republic/Central African Republic, 20 (17.0%) Rare/atypical, and 13 (11.1%) Benin/Benin. The frequency of the α3.7 deletion was 1.71% as homozygous (−α3.7/−α3.7) and 11.9% as heterozygous (−α3.7/αα). The only significant association in respect to haplotypes was related to the mean corpuscular volume. The presence of alpha-thalassemia was significantly associated to decreases in mean corpuscular volume, mean corpuscular hemoglobin and reticulocyte count and to an increase in the red blood cell count. There were no significant associations of βS-globin haplotypes and alpha-thalassemia with clinical manifestations. Conclusions: In the study population, the frequency of alpha-thalassemia was similar to published data in Brazil with the Central African Republic haplotype being the most common, followed by the Benin haplotype. βS-globin haplotypes and interaction between alpha-thalassemia and sickle cell anemia did not influence fetal hemoglobin concentrations or the number of clinical manifestations...

Glomerular filtration rate is altered in children with sickle cell disease: a comparison between Hb SS and Hb SC

BACKGROUND Renal failure is common among older patients with sickle cell disease; this is preceded by subclinical glomerular hyperfiltration. Data about renal function of adults with sickle cell disease have been reported, but data on children is scarce, especially when comparing heterozygotic and homozygotic patients. OBJECTIVE The goal of this study was to investigate the glomerular filtration rate of heterozygotic and homozygotic children with sickle cell disease. METHODS The glomerular filtration rate of 11 children with sickle cell disease [7 homozygotic (SS) and 4 heterozygotic (SC)] with a mean age of 11 years (standard deviation: ± 5 years) was evaluated using standard laboratory techniques. Results are presented as descriptive analysis. RESULTS Our results suggest that glomerular hyperfiltration is present in children with sickle cell disease; this is more evident in homozygotic than heterozygotic children. CONCLUSION There is evidence of a need to monitor the renal function of children with sickle cell disease when special attention should be paid to homozygotic patients.

Homozygous sickle cell disease in Uganda and Jamaica a comparison of Bantu and Benin haplotypes / La anemia de células falciformes homocigóticas en Uganda y Jamaica comparación de haplotipos Bantú y Benin

OBJECTIVE: To compare the haematological and clinical features of homozygous sickle cell (SS) disease in Bantu and Benin haplotypes in a cross-sectional study of 115 Ugandan patients attending the Sickle Cell Clinic at Mulago Hospital, Kampala, Uganda, with 311 patients in the Jamaican Cohort Study. METHODS: This involved comparison of clinical features and haematology with special reference to genetic determinants of severity including fetal haemoglobin levels, beta-globin haplotype and alpha thalassaemia status. RESULTS: The Bantu haplotype accounted for 94% of HbS chromosomes in Ugandan patients and the Benin haplotype for 76% of HbS chromosomes in Jamaica. Ugandan patients were marginally more likely to have alpha thalassaemia, had similar total haemoglobin and fetal haemoglobin levels but had higher reticulocyte counts and total bilirubin levels consistent with greater haemolysis. Ugandan patients had less leg ulceration and priapism, but the mode of clinical presentation, prevalence of dactylitis, features of bone pain and degree of delay in sexual development, assessed by menarche, were similar in the groups. In Ugandan patients, a history of anaemic episodes was common but these were poorly documented. CONCLUSION: The haematological and clinical features of the Bantu haplotype in Uganda were broadly similar to the Benin haplotype in Jamaica except for less leg ulceration and priapism and possibly greater haemolysis among Ugandan subjects. Anaemic episodes in Uganda were treated empirically by transfusion often without a clear diagnosis; better documentation including reticulocyte counts and observations on spleen size is necessary to evolve appropriate models of care.

OBJETIVO: Comparar los rasgos clínicos de la anemia de células falciformes homocigóticas (SS) en los haplotipos Bantú y Benin en un estudio transversal de 115 pacientes ugandeses que asisten a la Clínica de la anemia de células falciformes en el Hospital de Mulago, Kampala, Uganda, con 311 pacientes en un estudio de cohorte jamaicano. MÉTODOS: El estudio conllevó la comparación de los rasgos clínicos y hematológicos con referencia especial a los determinantes genéticos de la severidad, incluyendo los niveles de la hemoglobina fetal, haplotipos del gen de la globina beta, y el estado de la alfa talasemia. RESULTADOS: El haplotipo Bantú dio cuenta del 94% de los cromosomas HbS en los pacientes ugandeses, en tanto que los haplotipos Benin dieron cuenta del 76% de los cromosomas de HbS en Jamaica. Los pacientes de Uganda presentaron una probabilidad marginalmente mayor de alfa talasemia, tenían niveles similares de hemoglobina total y hemoglobina fetal, pero en cambio presentaban conteos más altos de reticulocitos así como niveles mayores de bilirrubina total, en correspondencia con una mayor hemólisis. Los pacientes ugandeses presentaban menor ulceración de las piernas y priapismo, pero el modo de presentación clínica, la prevalencia de dactilitis, los rasgos de dolor óseo, y el grado de retraso en el desarrollo sexual, evaluado por la menarquia, fueron similares en todos los grupos. Los pacientes de Uganda se caracterizaron comúnmente por una historia de episodios de anemia, pobremente documentados. CONCLUSIÓN: Los rasgos clínicos y hematológicos del haplotipo Bantú en Uganda fueron considerablemente similares al haplotipo Benin en Jamaica, salvo por una menor presencia de ulceración de las piernas y priapismo, así como posiblemente mayor hemólisis entre los sujetos de Uganda. Los episodios de anemia en Uganda fueron tratados empíricamente mediante transfusión, a menudo sin un diagnóstico claro. Se necesita una mejor documentación - incluyendo conteos de reticulocitos - así como observaciones del tamaño del bazo, a fin de desarrollar modelos de cuidado apropiados.

Sickle cell disease: acute clinical manifestations in early childhood and molecular characteristics in a group of children in Rio de Janeiro

OBJECTIVE: To describe clinical events of sickle cell disease and the correlation with β-globin haplotypes and α-thalassemia in under 6-year-old children. METHODS: A retrospective study was conducted of under 6-year-old children from the neonatal screening program in Rio de Janeiro. Forty-eight male and 48 female children were enrolled in this study, 79 with sickle cell anemia and 17 with hemoglobin SC. The mean age was 29.9 (standard deviation = 20.9) months, 62 (16.2 ± 8.6) were aged between 0-3 years old and 34 (54.9 ± 11.3) were from 3-6 years old. Painful events, acute splenic sequestration, hemolytic crises, hand-foot and acute chest syndromes and infections were evaluated. RESULTS: The events were more frequent in under 3-year-old children, 94% of children had at least one episode. Infection was the most common event affecting 88.5% of children. Acute splenic sequestration took place earlier, while painful crises and acute chest syndromes in under 6-year-old children. Thal-α 3.7 was observed in 20.9% of cases. Bantu was the most frequent haplotype found, followed by Benin. No correlation was observed between clinical events and β-globin haplotypes. Children with sickle cell anemia and α-thalassemia have less infectious events. No correlation was found among these polymorphisms and clinical events, however, the majority of children with Bantu/Bantu and without α-thalassemia had more clinical events.

a talasemia no deleción en España: Índices hematológicos anormales y su estudio molecular / No Deletion a Thalassaemia in Spain: Abnormal hematological index and molecular study

Las a talasemias en la mayoría de los casos es debida a deleciones que afectan a uno o a los dos genes a, siendo poco frecuente los casos debidos a mutaciones puntuales, inserciones o deleciones de pocos pares de bases, los cuales se han denominado a talasemias no deleción. Se determinó la incidencia de la a talasemia no deleción en los pacientes con a talasemia, mediante biología molecular. Se estudiaron 517 individuos remitidos al Hospital Clínico San Carlos, centro de referencia de estudios moleculares de Talasemias en Madrid- España, entre Enero del 2001 a Diciembre del 2003, en los que se había descartado ferropenia y presentaban microcitosis, hipocromía, Hb A2, Hb F y EEF de Hbs normales. Se estudiaron los 2 tipos de a talasemia no deleción más descritas en el Mediterráneo: 1) aHph debida a la deleción de 5 bp en el IVS I y 2) aNco a un cambio en el codón de iniciación del gen. De los 517, 40 presentaban una a talasemia no deleción (7,7%). De éstos, 28 fueron positivos para aHph del gen a2, 24 en estado heterocigoto, 1 homocigoto y 3 dobles heterocigotos asociados con la deleción 3,7 kb. Los 12 restantes resultaron positivos para la aNco del gen a2, 10 heterocigotos, 1 homocigoto y 1 doble heterocigoto asociado con la deleción 4,2 kb. La a talasemia no deleción representa < 8% de los casos de a talasemia en nuestro medio. La aHph es el tipo de a talasemia no deleción más frecuente y cuyas anormalidades hematológicas son más manifiestas que las presentadas en los casos de aNco.

The a thalassaemia diseases in most cases are caused by deletions that affect one or two of the a genes, being less frequent the cases due to punctual mutations, insertions or deletions of a few pairs of bases, which have been denominated no deletion a thalassaemias. The objective of this investigation was to determine the incidence of the no deletion a thalassaemia in patients with a thalassaemia using molecular biology techniques. We studied 517 individuals of the San Carlos Hospital (Thalassemia Molecular Research Center, Madrid-Spain) between January 2001 and December 2003, in whom iron deficiency anemia had been ruled out, that presented microcytosis and hypochromia and that presented normal HbA2, HbF and EEF from normal Hbs. The two types of no deletion a thalassaemia most frequently described in the Mediterranean were studied: 1) a Hph due to deletion of 5bp in the IVS I and 2) aNco due to a change in the initiation codon of the gene. Of the 517 cases studied, 40 (7.7% of the cases) represented a no deletion a thalassaemia. Of these cases, 28 were positive for aHph of the a2 gene, 24 in the heterozygote state, one homozygote and three double heterozygotes associated with the 3,7 kb deletion. The remaining 12 cases were positive for the aNco of the a2 gene, 10 heterozygotes, one homozygote and one double heterozygote associated with the 4,2 kb deletion. The no deletion a thalassaemias represent < 8% from the cases in our environment. The aHph is the most frequent type of no deletion a thalassaemia and its haematological abnormalities are more manifest that the ones present in the cases of aNco.