Polymorphisms in the heme oxygenase-1 and bone morphogenetic protein receptor type 1b genes and estimated glomerular filtration rate in Brazilian sickle cell anemia patients

ABSTRACT Introduction Mutations affecting genes involved in oxidative and signaling pathways may be associated with kidney disease in sickle cell anemia. We determined the allele and genotype frequencies of some polymorphisms in the promoter regions of the Heme Oxygenase-1 (HMOX1) [rs2071746 (A > T) and (GT)n repeats, short (S) and long (L) alleles] and Bone Morphogenetic Protein Receptor type-1B (BMPR1B) [rs17022863 (A > G), rs4331783 (A > G) and rs1470409 (A > G)] genes in 75 adult patients with sickle cell anemia and 160 healthy controls and investigated whether these polymorphisms may influence the estimated glomerular filtration rate for the patients. Methods The single nucleotide polymorphisms were genotyped using the TaqMan assays, the HMOX1(GT)n repeats were determined by polymerase chain reaction fragment size analysis and the estimated glomerular filtration rate was calculated by the Modification of Diet in Renal Disease formula. Results Regarding the HMOX1rs2071746, the estimated glomerular filtration rate median was significantly higher in TT patients (p = 0.019), including when TT was compared with AT + AA (p = 0.009); for the (GT)n repeats, the estimated glomerular filtration rate medians of SS, SL and LL significantly differed (p = 0.009), being the LL estimated glomerular filtration rate median significantly higher, when compared with the LS + SS (p = 0.005). These results suggest that both the homozygotes, TT for rs2071746 and LL for (GT)n repeats, lead to a higher risk of developing renal complications. Concerning the BMPR1B, the frequencies of GG for rs17022863 and AA for rs4331783 were significantly higher in patients than in controls (p = 0.002 and p = 0.008, respectively), however no association with estimated glomerular filtration rate was found. Conclusion These results contribute to a better understanding of the genetic factors related to the development of nephropathy in sickle cell anemia patients.

Rare α0-thalassemia deletions detected by MLPA in five unrelated Brazilian patients

Abstract Alpha-thalassemias are among the most common genetic diseases in the world. They are characterized by hypochromic and microcytic anemia and great clinical variability, ranging from a practically asymptomatic phenotype to severe anemia, which can lead to intrauterine or early neonatal death. Deletions affecting the α-globin genes, located on chromosome 16p13.3, are the main causes of α-thalassemia. Multiplex ligation-dependent probe amplification (MLPA) can be used to detect rearrangements that cause α-thalassemia, particularly large deletions involving the whole α cluster and/or deletions in the HS-40 region. Here, MLPA was used to investigate the molecular basis of α-thalassemia in five unrelated patients, three of whom had Hb H disease. In addition to the -α3.7 deletion identified in the patients with Hb H disease, four different α0 deletions removing 15 to 225 kb DNA segments were found: two of them remove both the α genes, one affects only the regulatory element (HS-40) region, and another one extends over the entire α cluster and the HS-40 region. These results illustrate the diversity of α-thalassemia deletions in the Brazilian population and highlight the importance of molecular investigation in cases that present with microcytosis and hypochromia without iron deficiency and normal or reduced Hb A2 levels..

Socioeconomic and demographic characteristics of sickle cell disease patients from a low-income region of northeastern Brazil

To characterize the socioeconomic and demographic aspects of sickle cell disease patients from the state of Rio Grande do Norte (RN), Northeast Brazil, and their adherence to the recommended treatment. Methods: This cross-sectional descriptive study was performed at referral centers for the treatment of hematological diseases. One hundred and fifty-five unrelated individuals with sickle cell disease who went to these centers for outpatient visits were analyzed. All the patients, or their caregivers, were informed about the research procedures and objectives, and answered a standardized questionnaire. Results: The patients were predominantly younger than 12 years old, self-declared as mulatto, lived in small towns fairly distant from the referral center, and had low education and socioeconomic levels. Individuals who were ten or younger were diagnosed at an earlier age. Almost 50% of the patients were taking hydroxyurea, 91.4% reported having received pneumococcal/meningococcal vaccinations and 76.1% received penicillin as antibiotic prophylaxis. However, the majority of them reported having difficulties following the recommendations of the physicians, mainly in respect to attaining the prescribed medications and transportation to the referral centers. Conclusion: These individuals have a vulnerable socioeconomic situation that can lead to an aggravation of their general health and thus deserve special attention from the medical and psychosocial perspectives. Thus, it is necessary to improve public policies that provide Brazilian sickle cell disease patients with better access to medical treatment, living conditions, and integration into society.

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.

Hb Southampton B106 G8 Leu PRO, CTG CCG in a Uruguayan woman

Hemoglobin Southampton (also known as hemoglobin Casper) is a rare hemoglobin structural variant resulting from a substitution of a leucine residue for proline at codon beta106 [beta106(G8)Leu→Pro, CTG→CCG]. It is very unstable and associated with severe hemolytic anemia. We detected this mutation in a 37-year-old Uruguayan woman with a history of severe chronic hemolytic anemia since her childhood. According to our knowledge this is the first time that this variant has been found in the Uruguayan population.

Determination of beta S haplotypes in patients with sickle-cell anemia in the state of Rio Grande do Norte, Brazil

βS haplotypes were studied in 47 non-related patients with sickle-cell anemia from the state of Rio Grande do Norte, Brazil. Molecular analysis was conducted by PCR/RFLP using restriction endonucleases XmnI, HindIII, HincII and HinfI to analyze six polymorphic sites from the beta cluster. Twenty-seven patients (57.5 percent) were identified with genotype CAR/CAR, 9 (19.1 percent) CAR/BEN, 6 (12.8 percent) CAR/CAM, 1 (2.1 percent) BEN/BEN, 2 (4.3 percent) CAR/Atp, 1 (2.1 percent) BEN/Atp and 1 (2.1 percent) with genotype Atp/Atp. The greater frequency of Cameroon haplotypes compared to other Brazilian states suggests the existence of a peculiarity of African origin in the state of Rio Grande do Norte.

Characterization of beta-thalassemia mutations in patients from the state of Rio Grande do Norte, Brazil

35 unrelated individuals were studied for characterization as either heterozygous or homozygous for beta-thalassemia. Molecular analysis was done by PCR/RFLP to detect the mutations most commonly associated with beta-thalassemia (β0IVS-I-1, β+IVS-I-6, and β039). In the patients who showed none of these mutations, the beta-globin genes were sequenced. Of the 31 heterozygous patients, 13 (41.9 percent) had the β+IVS-I-6 mutation, 15 (48.4 percent) the β0IVS-I-1 mutation, 2 (6.5 percent) the β+IVS-I-110 mutation and 1 (3.2 percent) the β+IVS-I-5 mutation. IVS-I-6 was detected in the four homozygotes. The mutation in codon 39, often found in previous studies in Brazil, was not detected in the present case. This is the first study aiming at identifying mutations that determine beta-thalassemia in the state of Rio Grande do Norte.

Hb H disease resulting from the association of an αº-thalassemia allele [-(α)20.5] with an unstable α-globin variant [Hb Icaria]: First report on the occurrence in Brazil

Hb H Disease is caused by the loss or inactivation of three of the four functional a-globin genes. Patients present chronic hemolytic anemia and splenomegaly. In some cases, occasional blood transfusions are required. Deletions are the main cause of this type of thalassemia (α-thalassemia). We describe here an unusual case of Hb H disease caused by the combination of a common αº deletion [-(α)20.5] with a rare point mutation (c.427T > A), thus resulting in an elongated and unstable α-globin variant, Hb Icaria, (X142K), with 31 additional amino-acid residues. Very high levels of Hb H and Hb Bart's were detected in the patient's red blood cells (14.7 and 19.0 percent, respectively). This is the first description of this infrequent association in the Brazilian population.

Genética das doenças hematológicas: as hemoglobinopatias hereditárias: [revisão] / The genetics of blood disorders: hereditary hemoglobinopathies: [review]

OBJETIVO: Sumarizar os dados disponíveis na literatura recente sobre os aspectos fisiopatológicos, de diagnóstico e tratamento das doenças falciformes e da talassemia β, hemoglobinopatias hereditárias de maior relevância nas populações. FONTES DOS DADOS: MEDLINE e SciELO, utilizando os termos hemoglobinopatias hereditárias, doenças falciformes e talassemia beta, no período de 2003 a maio de 2008. Dois livros e dois capítulos de livro foram também incluídos. SÍNTESE DOS DADOS: Foram encontrados mais de 2.000 artigos, sendo selecionados aqueles de maior pertinência e amplitude. CONCLUSÕES: As taxas de morbidade e a mortalidade das doenças falciformes e da talassemia β são ainda bastante expressivas e constituem importante desafio. Um maior conhecimento dos mecanismos fisiopatológicos tem permitido avanços significativos nas formas de tratamento e prevenção dessas doenças.

OBJECTIVE: To summarize recently published data on the pathophysiology, diagnosis and treatment of sickle cell diseases and β-Thalassemias, the most relevant hereditary hemoglobinopathies in the global population. SOURCES: Searches were run on the MEDLINE and SCIELO databases, limited to the period from 2003 to May 2008, using the terms hereditary hemoglobinopathies, sickle cell diseases and β-thalassemia. Two books and two chapters were also included. SUMMARY OF THE FINDINGS: More than 2,000 articles were identified; those providing the most important information and broadest views were selected. CONCLUSIONS: Morbidity and mortality rates from sickle cell diseases and β-thalassemia are still very high and represent an important challenge. Increased understanding of pathophysiological aspects has lead to significant improvements in treatment and prevention of these diseases.

Identificação e caracterização de variantes novas e raras da hemoglobina humana: [revisão] / Identification of characterization of novel and rare variants of human hemoglobin: [review]

As anormalidades estruturais da hemoglobina estão entre as doenças genéticas mais comumente encontradas nas populações humanas. O Laboratório de Hemoglobinopatias do Departamento de Patologia Clínica da Faculdade de Ciências Médicas da Universidade Estadual de Campinas - Unicamp, localizado em Campinas, no estado de São Paulo, região Sudeste do Brasil, realizou, em seus 27 anos de existência, cerca de 130.000 diagnósticos. Entre as variantes estruturais detectadas, as hemoglobinas S, C e D-Punjab foram, como esperado, as mais freqüentes, porém um número expressivo de outras hemoglobinas anômalas, novas e raras, também foi encontrado. Esses achados estão sumarizados no presente artigo.

Hemoglobin structural abnormalities are among the most commonly found human genetic diseases. The Laboratory of Hemoglobinopathies in the Clinical Pathology Department of the Medical Sciences School of the State University in Campinas - Unicamp, São Paulo, Southeastern Brazil, carried out, in its 27 years of activity, about 130,000 diagnoses. As expected, hemoglobins S, C and D were the most frequently observed variants, but an expressive number of other abnormal, novel and rare hemoglobins, was also detected. These findings are summarized in the present article.

Haptoglobin study in myasthenia gravis / Estudo sobre a haptoglobina na miastenia grave

OBJECTIVE: A cross-sectional study of haptoglobin (Hp) in myasthenia gravis (MG) was designed, with the objective to identify its values and correlate them with different disease status. METHOD: 46 patients were enrolled in the study, all having disease severity established according to the quantitative myasthenia gravis strength scores (QMGSS). Based on the functional scale determined by Myasthenia Gravis Foundation of America (MGFA) recommendations, patients were classified as having: complete stable remission (CSR; n=10); minimal manifestations-0 (MM0; n=6), minimal manifestations-1 (MM1; n=4); pharmacological remission (PR; n=6). Two other groups participated: thymomatous patients (T; n=10) and patients without imunosuppression or thymectomy, until the assessment for Hp (WIT; n=10). Hp dosage was done by immunonephelometry, blindly to clinical data. Student's t-test, Anova test and linear regression were employed for statistical analyses. RESULTS: Statistically significant differences occurred between CSR+MM0xWIT groups (86.62x157.57, p<0.001) and PR+MM1xWIT groups (73.93x157.57, p<0.001). Linear regression showed correlation between Hp levels and QMGSS (r=0.759, p<0.001). CONCLUSION: Our results suggest that Hp may be useful in clinical practice as a disease severity marker in MG.

OBJECTIVO: Desenhou-se estudo transversal sobre a haptoglobina (Hp) na miastenia grave (MG) com o objetivo de identificar seus valores e correlacioná-los a diferentes condições na doença. MÉTODO: 46 pacientes foram incluídos, todos tendo a gravidade da doença estabelecida segundo escores internacionais (QMGSS). Os pacientes tiveram seu estado funcional determinado de acordo com a Myasthenia Gravis Foundation of América (MGFA) e classificados em: remissão completa estável (CSR; n=10); mínima manifestação-0 (MM0; n=6), mínima manifestação-1 (MM1; n=4); remissão farmacológica (PR; n=6). Dois outros grupos participaram: pacientes timomatosos (T; n=10) e pacientes sem imunossupressão ou timectomia, até o momento da inclusão no estudo (WIT; n=10). A dosagem de Hp foi realizada por imunonefelometria, de modo cego quanto à clínica. As análises estatísticas incluíram o teste de Student, Anova e regressão linear. RESULTADOS: Observou-se diferença significativa entre os grupos CSR+MM0xWIT (86,62x157,57, p<0,001) e entre PR+MM1xWIT (73,93x157,57, p<0,001). A regressão linear mostrou correlação positiva entre os valores de Hp e os escores QMGSS (r=0,759, p<0,001). CONCLUSÃO: O estudo sugere que valores altos de Hp se correlacionaram a maior gravidade da MG.

Polymorphism of human haptoglobin and its clinical importance: [review]

Haptoglobin (Hp) is a plasma glycoprotein, the main biological function of which is to bind free hemoglobin (Hb) and prevent the loss of iron and subsequent kidney damage following intravascular hemolysis. Haptoglobin is also a positive acute-phase protein with immunomodulatory properties. In humans, the HP locus is polymorphic, with two codominant alleles (HP1 and HP2) that yield three distinct genotypes/phenotypes (Hp1-1, Hp2-1 and Hp2-2). The corresponding proteins have structural and functional differences that may influence the susceptibility and/or outcome in several diseases. This article summarizes the available data on the structure and functions of Hp and the possible effects of Hp polymorphism in a number of important human disorders.

Molecular characterization of alpha-thalassemia in the Mexican population / Caracterización molecular de talasemia alfa en una población mexicana

Background. α-Thalassemia (α-Thal) has been poorly characterized at the molecular level in Mexico. Methods. 106 consecutive individuals identified in Laboratorios Clínicos de Puebla, with either hypochromia (MCH < 24 pg) and/or microcytosis (MCV < 75 fl in women or < 80 fl in man), without iron deficiency, with or without anemia were investigated in this study, along a 16 month-period, α and β-Thal were looked for, the former were characterized at the molecular level. Results. Out of the 106 consecutive cases with hypochromia and/or microcytosis and normal levels of protoporphyrin zinc complex, 48 cases (45.3%) had thalassemia (37 cases of β-Thal and 11 cases of α-Thal), whereas in 58 cases (54.7%) a definite diagnosis could not be established. Of the α-Thal cases, 8 were heterozygous and two were homozygous for the -α3.7 deletion, whereas one case was heterozygous for the α2Hph allele. Conclusions. Only few of the α-Thal alleles tested were found, thus the α-thalassemic mutations, present in the studied population, seem to be rather heterogeneous.

Antecedentes. En México, la α-talasemia (α-Thal) ha sido pobremente caracterizada a nivel molecular. Mátodos. Se estudiaron 106 individuos consecutivos identificados en los Laboratorios Clínicos de Puebla, con hipocromia (CMH < 24 pg) y lo microcitosis (VCM < 75 fl en mujeres o 80 fl en hombres), sin deficiencia de hierro, con o sin anemia, durante un periodo de 16 meses. Se investigaron α y β-Thal; las primeras fueron caracterizadas a nivel molecular. Resultados. De los 106 casos consecutivos estudiados con hipocromia y/o microcitosis, y niveles normales del complejo de protoporfirina-cinc, 48 casos (45.3%) tenían talasemias (37 de ellos β-Thal y 11 α-Thal), mientras que en 58 casos (54.7%) no pudo establecerse un diagnóstico definitivo. De las talasemias α, ocho casos eran heterocigotos y dos homocigotos para la deleción -α3.7, mientras que sólo un caso resultó heterocigoto para el alelo α2Hph. Conclusiones. De los alelos α-Thal estudiados sólo se encontraron algunos, de lo que se infiere que en la población estudiada esas mutaciones parecen ser bastante heterogáneas.

Alpha-thalassemia, HbS, and beta-globin gene cluster haplotypes in two Afro-Uruguayan sub-populations from northern and southern Uruguay

Hemoglobinopathies are the most common monogenic disorders worldwide; however, they have never been systematically studied from a genetic perspective in Uruguay. In this study, we determined the frequencies of hemoglobin variants in Afro-Uruguayans. A sample of 52 healthy unrelated Afro-Uruguayans from the northern (N = 28) and southern (N = 24) regions of the country was analyzed. Eight individuals (15.4 percent) were heterozygous for -alpha3,7thalassemia; seven of them (29.2 percent) were originally from the southern region, whereas one of them (3.6 percent) was from the northern region; the differences between both regions were statistically significant (p = 0.016 +/-0.003). The only structural mutation detected was betaS, which is typical of African populations. Four individuals (10 percent) were heterozygous for betaS, three of them (13.6 percent) from the South, and one (5.6 percent) from the North. The betaS haplotypes were analyzed in eight individuals: two were homozygous betaS/betaS, two were heterozygous betaS/betathal, and four were heterozygous betaS/betaª. This haplotype distribution (60 percent Bantu, 20 percent Benin, and 20 percent Bantu A2) is in agreement with historical records reporting a predominantly Bantu origin for the enslaved Africans brought to Uruguay. Even though this is a preliminary study, due to the small sample size, our results are suggestive of a relatively high incidence of hemoglobinopathies in the Afro-Uruguayan population.

Polycythemia and Hb Coimbra [beta 99 (G1) Asp -> Glu] in Brazil

We report the clinical and laboratory findings concerning three unrelated Brazilian patients investigated for polycythemia, whose definitive diagnosis could only be established after the presence of Hb Coimbra (b99 Asp ® Glu) was demonstrated. This illustrates the importance of properly investigating hereditary hemoglobinopathies in cases of erythrocytosis because in some populations variants with high oxygen affinity may be more frequent than expected but go undetected when conventional electrophoresis is used as the sole detection procedure.

Haptoglobin phenotypes in Brazilian patients with leukemia

Os fenótipos de haptoglobina (HP) foram determinados em 188 pacientes brasileiros com os quatro principais tipos de leucemia (LMA, LMC, LLA e LLC) e comparados a 197 controles normais. A existência de associação entre a LMA, a LMC e a LLA e o gene HP-1 e o fenótipo HP 1-1, previamente sugerida na literatura, não foi confirmada no presente estudo. Uma prevalência maior de haptoglobinêmicos (HP0) foi verificada entre os pacientes, em concordância com estudos prévios.

Mild clinical expression of S-ß thalassemia in a Brazilian patient with the ß+ IVS-I- (T C) mutation

Nós caracterizamos a base molecular da talassemia ß em uma paciente negra brasileira, de 8 anos de idade, com um quadro clínico extremamente benigno de S-ß+ talassemia. A paciente tinha uma hemoglobina total de 10,1 g/dl, com 57 por cento de HbS. O sequenciamento direto do DNA, amplificado por PCR, revelou que a paciente é heterozigota da mutaçäo ß+IVS-I-6 (T C). Esta mutaçäo, algumas vezes referida como o tipo português de talassemia, foi encontrada em associaçäo com o polimorfismo C T no codon 2 do gene ß e, de nosso conhecimento, näo havia sido previamente descrita na populçäo negra brasileira.

Rapid identification of the association of hemoglobin D Punjab and hemoglobin S (HbD Punjab/HbS) by the polymerase chain reaction

A hemoglobina D-Punjab foi descrita em vários grupos étnicos, tanto em heterozigose simples quanto em associaçäo com Hb S ou ß-talassemia. Neste trabalho descrevemos uma paciente brasileira, negra de 10 anos de idade que apresentava características clínicas de doença falciforme. O padräo eletroforético sugeriu a associaçäo Hb S/Hb D. A mutaçäo da Hb D foi confirmada através da digestäo do fragmento amplificado do gene da globina ß com a enzima EcoRI e sequencialmente direto do fragmento amplificado. A mutaçäo muda uma base no codon 121 e abole o sítio de reconhecimento normal da enzima, possibilitando o reconhecimento do gene anormal em electroforese de gel de agarose. Estes dados representam a segunda descriçäo comprovada da associaçäo Hb S/Hb D no Brasil e indicam que a presença da Hb D deve ser investigada, pelo método aqui descrito, em casos de doença falciforme com padräo eletroforético anômalo