Impact of haemoglobin variants on the diagnostic sensitivity of glycated haemoglobin (HbA1c) assay methodologies in sub-Saharan Africa: a laboratory-based method validation study.

Introduction: the utility of glycated haemoglobin (HbA1c) for the diagnosis and monitoring of diabetes in sub-Saharan Africa is uncertain due to limited data on the performance of the available HbA1c assay methods in this population, which has a high prevalence of haemoglobin variants. We aimed to compare the diagnostic accuracy of the major HbA1c methodologies (Boronate Affinity, Capillary Electrophoresis, High Performance Liquid Chromatography, Immunoassay) in an African population, and assess the impact of the common haemoglobin variant HbAS (sickle cell trait). Methods: whole blood samples were obtained from 182 individuals living with type 2 diabetes in Uganda. HbA1c values for each method were compared to average glucose measured over 14 days by continuous glucose monitoring (CGM). To determine concordance, the three HbA1c assay methods were compared to the capillary electrophoresis method. Results: there was a strong correlation between CGM average glucose levels and all four HbA1c methodologies (r=0.81-0.89) which did not differ in those with and without HbAS (present in 37/182 participants). The presence of HbAS did not alter the relationship between HbA1c and CGM glucose for any assay (p for interaction >0.2 for all methods). Diagnostic accuracy for CGM average glucose thresholds of 7 and 10mmol/L was similar across methods (area under the receiver operating characteristic curve 0.80-0.84 and 0.76-0.84 respectively). The maximum bias between the HbA1c assay methodologies was 2 mmol/mol (2.07%). Conclusion: all major HbA1c technologies offer accurate and comparable HbA1c measurement even in this population with high prevalence of haemoglobin variants.

A high stable sample loading for analysis of adult alpha-thalassemia via the improved microarray isoelectric focusing of Hb species.

The isoelectric focusing has realized various improvements, including the protocols and creation of mIEF (microcolumn isoelectric focusing) instruments with excellent sensitivity for screening of diabetes and beta thalassemia. However, the problem of manual sample loading and hydration for the mIEF limits the operational capacity for stably detecting and quantitating most abnormal hemoglobin (Hb). Herein, we provided a high stable sample loading protocol for analysis of alpha thalassemia and Hb variants. In contrast to the previous volume of 20 µl, a 100 µl blood sample solution in this protocol was optimized with mixture of 6.4-7.5 and 3-10 pH carrier ampholytes, pI markers and loaded for 30 mins IPG microcolumn hydration. The hydrated microcolumn was then automatically loaded onto the mIEF chip array to which CH3COOH and NH4OH act as anodic and cathodic solutions. Lastly, the IEF was run for 9 mins. Hb H, Barts, A1c, F, A2 and CS were simultaneously separated and focused with higher resolution and sensitivity in quantifying H and Barts as low as 0.6 and 0.5 % respectively. Accordingly, there was an enhanced stability and linearity with a rapid assay time of 45 secs per sample. Moreover, analysis showed a fitting linear relationship with conventional technology at R2 = 0.9803 for H and R2 = 0.9728 for Barts thereby indicating greater accuracy confirmed by the AUC. Hence, the developed protocol could simply be employed for high stable and throughput batch sample loading of hydration, and accurate separation and quantitation of Hb variants for alpha and beta thalassemia.

An incidental finding of a hemoglobin E variant in a diabetic patient with an abnormal glycated hemoglobin level: a case report.

BACKGROUND: Glycated hemoglobin is a well-known marker for evaluating long-term glycemic control. However, the accuracy of glycated hemoglobin measurement can be affected by the presence of hemoglobin variants, which makes the determination and interpretation of glycated hemoglobin values in terms of glycemic control not only difficult but also misleading. Here we present the first ever case of a patient with type 2 diabetes with hemoglobin E from Nepal, diagnosed incidentally because of spurious glycated hemoglobin levels. CASE PRESENTATION: A 45-year-old Hindu Mongolian female with a history of type 2 diabetes for around 9 years but not very compliant with follow-ups was referred to our facility for plasma fasting and postprandial blood glucose levels and glycated hemoglobin. Fasting and postprandial blood sugars were found to be high. A consistent very low glycated hemoglobin by two different high-performance liquid chromatography (HPLC) methods compelled us to call the patient for a detailed clinical history and for the records of investigations done in the past. The patient has been a known case of type 2 diabetes for around 9 years and presented irregularly for follow-up visits. Around 4 years ago, she presented to a healthcare facility with fatigue, severe headaches, pain in the abdomen, discomfort, and dizziness for a couple of months, where she was shown to have high blood glucose. She was referred to a tertiary-level hospital in Kathmandu, where she was prescribed metformin 500 mg once daily (OD). Due to her abnormal hemoglobin A1c reports, she was then sent to the National Public Health Laboratory for repeat investigations. Her blood and urine investigations were sent. Complete blood count findings revealed high red blood cell and white blood cell counts, a low mean corpuscular volume, and a high red cell distribution width-coefficient of variation. Other parameters, including serum electrolytes, renal function tests, liver function tests, and urine routine examinations, were within normal limits. A peripheral blood smear revealed microcytic hypochromic red cells with some target cells. Hemoglobin electrophoresis showed a very high percentage of hemoglobin E, a very low percentage of hemoglobin A2, and normal proportions of hemoglobin A and hemoglobin F. A diagnosis of homozygous hemoglobin E was made, and family screening was advised. CONCLUSIONS: Clinicians should be aware of the limitations of glycated hemoglobin estimation by ion exchange high-performance liquid chromatography in patients with hemoglobin E and other hemoglobin variants. If the clinical impression and glycated hemoglobin test results do not match, glycated hemoglobin values should be determined with a second method based on a different principle, and glycemic status should be confirmed through alternative investigations, preferably those that are not influenced by the presence of hemoglobin variants (for example, boronate affinity chromatography, fructosamine test, glycated albumin test, the oral glucose tolerance test, continuous glucose monitoring, etc.). Consistent or even doubtful results should also raise the suspicion of a hemoglobin variant, which should be confirmed through further evaluation and investigations.

First Family Case of Hemoglobinopathy Titusville in China with Falsely Low SpO2 and Unmeasurable SaO2.

BACKGROUND: Normal hemoglobin is a tetrameric structure, consisting of two alpha-globin chains and two nonalpha (beta, gamma, delta) chains. Hemoglobinopathies occur when the presence of gene mutations affect the molecular structure or expression of the globin chains. METHODS: We reported the case of a 9-year-old Chinese girl who presented with abnormal low oxygen saturation values on pulse oximetry and no oximetry results were obtained during blood gas analysis (BGA). RESULTS: High-performance liquid chromatography (HPLC) and capillary electrophoresis demonstrated that the presence of a low oxygen affinity hemoglobin variant, characterized as hemoglobin Titusville, was proven by gene sequencing. The patient's mother and aunt also carry the hemoglobin variant, representing the first Chinese family case reported. CONCLUSIONS: Hemoglobin Titusville is a rare genetic hemoglobin structural defect. early diagnosis can help patients and clinicians avoid unnecessary anxiety and costly or excessive clinical investigations.

Hb Hebei [α20 (B1) His→Leu; HBA2:C.62A > T]: A Novel Hemoglobin Variant Found during Measurement of Glycated Hemoglobin.

We report a novel hemoglobin (Hb) variant found in a 34-year-old Chinese male during a routine measurement of glycated hemoglobin. The variant resulted in a P3 peak of 27.5% of the total Hb on high performance liquid chromatography (HPLC) with a glycated hemoglobin mode. However, no abnormal Hb peaks were observed in capillary electrophoresis (CE) with 3.1% Hb A2 and 96.9% Hb A. The amino acid substitution was determined by Sanger sequencing as α20 (B1) His→Leu; the corresponding DNA mutation was identified as CAC > CTC at the first position of codon 20 of the α-chain. This is the first description of the mutation, and we have named it Hb Hebei for the region of origin of the proband.

Fetal hemodynamic changes and mitochondrial dysfunction in myocardium and brain tissues in response to anemia: a lesson from hemoglobin Bart's disease.

OBJECTIVE: Whether or not the effects of anemia in the early phase, while the fetuses attempts to increase cardiac output to meet oxygen requirement in peripheral organs, is detrimental to the fetal developing vital organs is little-known. The objective of this is to compare prenatal cardiovascular changes and post-abortal cellular damages in the myocardium as a pumping organ and the brain as a perfused organ between anemic fetuses (using fetal Hb Bart's disease as a study model) in pre-hydropic phase and non-anemic fetuses. METHODS: Fetuses affected by Hb Bart's disease and non-anemic fetuses at 16-22 weeks were recruited to undergo comprehensive fetal echocardiography. Cord blood analysis was used to confirm the definite diagnosis of fetal Hb Bart's disease and normal fetuses. Fetal cardiac and brain tissues were collected shortly after pregnancy termination for the determination of oxidative stress and mitochondrial function, including mitochondrial ROS production and mitochondrial membrane changes. RESULTS: A total of 18 fetuses affected by Hb Bart's disease and 13 non-anemic fetuses were recruited. The clinical characteristics of both groups were comparable. The affected fetuses showed a significant increase in cardiac dimensions, cardiac function, cardiac output and brain circulation without deteriorating cardiac contractility and preload. However, in the affected fetuses, mitochondrial dysfunction was clearly demonstrated in brain tissues and in the myocardium, as indicated by a significant increase in the membrane potential change (p-value < 0.001), and a significant increase in ROS production in brain tissues, with a trend to increase in myocardium. The findings indicated cellular damage in spite of good clinical compensation. CONCLUSION: The new insight is that, in response to fetal anemia, fetal heart increases in size (dilatation) and function to increase cardiac output and blood flow velocity to provide adequate tissue perfusion, especially brain circulation. However, the myocardium and brain showed a significant increase in mitochondrial dysfunction, suggesting cellular damage secondary to anemic hypoxia. The compensatory increase in circulation could not completely prevent subtle brain and heart damage.

A comparative evaluation of the analytical performances of premier resolution-high-performance liquid chromatography (PR-HPLC) with capillary zone electrophoresis (CZE) assays for the detection of hemoglobin variants and the quantitation of HbA0, A2, E, and F.

OBJECTIVES: Hemoglobinopathies, including thalassemia and hemoglobin (Hb) variants, are common hematological disorders in tropical countries. Accurate and precise separation of hemoglobin types and reliable quantitation are necessary for differential diagnosis of these disorders. METHODS: We have evaluated the analytical performances of premier resolution-high-performance liquid chromatography (PR-HPLC; Trinity Biotech, Co. Wicklow, Ireland) to assist in the presumptive diagnosis of thalassemia and Hb variants commonly found in Southeast Asian countries. HbA0, HbA2, HbE, and HbF levels were separated and quantified in 120 blood samples from unrelated adult subjects and compared with those analyzed by capillary zone electrophoresis (CZE; CAPILLARYS™ 2, Sebia, Norcross, GA, US). The Hb analysis patterns of Hb variants obtained from the PR-HPLC system were also compared to those obtained from HPLC (VARIANT II, ß-thalassemia Short Program, Bio-Rad, Laboratories, Hercules, CA, US) and CZE systems. RESULTS: The PR-HPLC had excellent precision with a coefficient of variation (CV) for HbA2 quantitation of 3.8 % within-run and 5.2 % between-run. The levels of HbA2/E quantified by the PR-HPLC system correlated well with those of the CZE system (r=0.997). In addition, thalassemia interpretation results obtained from the PR-HPLC and the CZE showed 100 % agreement. Moreover, chromatograms of the PR-HPLC were also comparable to those of VII-HPLC and CAP2-CZE electropherograms. CONCLUSIONS: The PR-HPLC system would be applicable to diagnose common forms of thalassemia and Hb variants in Southeast Asia.

Hemoglobina Denver, una causa de desaturación en oximetría de pulso. Reporte de caso en un paciente pediátrico / Hemoglobin Denver, a cause of desaturated pulse oximetry. A pediatric case report

Las hemoglobinopatías son trastornos genéticos que afectan a la molécula de hemoglobina (Hb). Las mutaciones en las cadenas a o b que alteran el tetrámero de Hb pueden modificar la capacidad de la molécula para unirse al oxígeno. Las hemoglobinopatías con baja afinidad al oxígeno pueden presentarse con cianosis y una lectura alterada de la oximetría de pulso, lo que lleva a pruebas innecesarias y, a veces, invasivas para descartar afecciones cardiovasculares y respiratorias. En el siguiente reporte de caso, presentamos a una paciente pediátrica, asintomática, que se presentó a la consulta por detección de desaturación en oximetría de pulso. Las pruebas de laboratorio iniciales mostraron una anemia normocítica, normocrómica. Las muestras de gas venoso demostraron una p50 elevada. Después de extensas herramientas de diagnóstico, se diagnosticó una variante de Hb con baja afinidad al oxígeno, Hb Denver.

Hemoglobinopathies are genetic disorders that affect the hemoglobin (Hb) molecule. Mutations in the alpha or beta chains altering the Hb tetramer may modify the molecule's oxygen-binding capacity. Hemoglobinopathies with low oxygen affinity may occur with cyanosis and an altered pulse oximetry reading, leading to unnecessary and sometimes invasive tests to rule out cardiovascular and respiratory conditions. In the case report described here, we present an asymptomatic pediatric patient who consulted for desaturated pulse oximetry. Her initial laboratory tests showed normocytic, normochromic anemia. Venous blood gas samples showed an elevated p50. After using extensive diagnostic tools, a variant of Hb with low oxygen affinity was diagnosed: Hb Denver.

HbA1c levels in individuals heterozygous for hemoglobin variants / Dosagem de hemoglobina glicada em heterozigotos para hemoglobinas variantes

Summary Objective: To evaluate the levels of glycated hemoglobin (HbA1c) in patients heterozygous for hemoglobin variants and compare the results of this test with those of a control group. Method: This was an experimental study based on the comparison of HbA1c tests in two different populations, with a test group represented by individuals heterozygous for hemoglobin variants (AS and AC) and a control group consisting of people with electrophoretic profile AA. The two populations were required to meet the following inclusion criteria: Normal levels of fasting glucose, hemoglobin, urea and triglycerides, bilirubin > 20 mg/dL and non-use of acetylsalicylic acid. 50 heterozygous subjects and 50 controls were evaluated between August 2013 and May 2014. The comparison of HbA1c levels between heterozygous individuals and control subjects was performed based on standard deviation, mean and G-Test. Results: The study assessed a test group and a control group, both with 39 adults and 11 children. The mean among heterozygous adults for HbA1c was 5.0%, while the control group showed a rate of 5.74%. Heterozygous children presented mean HbA1c at 5.11%, while the controls were at 5.78%. G-Test yielded p=0.93 for children and p=0.89 for adults. Conclusion: Our study evaluated HbA1c using ion exchange chromatography resins, and the patients heterozygous for hemoglobin variants showed no significant difference from the control group.

Resumo Objetivo: Avaliar os níveis de hemoglobina glicada em pacientes heterozigotos para hemoglobinas variantes e comparar os resultados deste exame com grupo controle. Método: Trata-se de um estudo experimental, baseado na comparação do exame de hemoglobina glicada de duas populações diferentes, sendo um grupo teste, representado por indivíduos heterozigóticos para hemoglobinas variantes (AS e AC) e um grupo controle, constituído por pessoas com perfil eletroforético AA. As duas populações verificadas devem obedecer ao critério de inclusão: glicemia de jejum, hemoglobina, ureia e triglicérides normais, bilirrubina > 20 mg/dL e não fazer uso de ácido acetilsalicílico. Foram avaliados 50 indivíduos heterozigotos e 50 controles no período de agosto de 2013 a maio de 2014. A comparação dos valores de hemoglobina glicada entre indivíduos heterozigóticos e controle foi realizada por meio do desvio padrão, média e teste G. Resultados: O estudo analisou um grupo teste e um grupo controle, ambos com 39 adultos e 11 crianças. A média dos adultos heterozigotos para HbA1c foi de 5,0%, o grupo controle apresentou índice de 5,7%. Já as crianças heterozigóticas obtiveram média de HbA1c de 5,11%, enquanto as normais apresentaram valores médios de 5,78%. O valor do teste G foi de p=0,9 para crianças e p=0,89 para adultos. Conclusão: Este estudo avaliou HbA1c pela metodologia de cromatografia de coluna com resinas de troca iônica, em que pacientes com heterozigoses para hemoglobinas variantes não apresentaram uma diferença significativa em relação ao grupo controle.

Anemia hemolítica grave causada por hemoglobina Southampton: Presentación de caso clínico / Severe hemolytic anemia due to hemoglobin Southampton: Case report

Las hemoglobinopatías estructurales son variantes de la hemoglobina caracterizadas por la síntesis de una molécula cualitativamente diferente de la normal. La mayoría son inocuas, mientras que otras ocasionan cambios fisicoquímicos que determinan manifestaciones clínicas de gravedad variable. En el caso de las hemoglobinas inestables, las alteraciones reducen la solubilidad y facilitan la formación de complejos de hemoglobina desnaturalizada (cuerpos de Heinz) que precipitan, lo cual daña la membrana y destruye prematuramente al eritrocito. Hasta la actualidad se han descrito 142 hemoglobinas inestables, muchas de ellas ocasionan hemólisis crónica, que puede exacerbarse por infecciones o por la ingesta de medicamentos o drogas oxidantes. La hemoglobina Southampton (también conocida como hemoglobina Casper) es una variante inestable que resulta de la sustitución de un residuo de leucina por uno de prolina, en el codón ß106 (CTG ?CCG, como consecuencia de la mutación c.320 T>C. Presentamos una niña con anemia hemolítica grave, esplenomegalia y requerimiento transfusional debidos a hemoglobina Southampton.

Variant hemoglobins are the result of different types of mutations that occur in the globin genes. In many cases, these hemoglobinopathies are harmless, while in others they determine alterations in the physical and chemical properties raising clinical manifestations of variable severity. In the unstable hemoglobinopathies, the changes reduce solubility, inducing the formation of precipitates of denaturated hemoglobin (Heinz bodies), which damage the membrane and finally destroy the red blood cells prematurely. Up to now, more than 142 different unstable hemoglobins have been described, most of them cause chronic hemolysis, increased by infections or drugs. We report the clinical presentation of an unstable hemoglobin (hemoglobin Southampton) in a girl with severe hemolytic anemia, splenomegaly and red blood cell requirement.

Molecular characterization of hemoglobin D Punjab traits and clinical-hematological profile of the patients / Caracterização molecular dos traços de hemoglobina D Punjab e perfil clínico-hematológico dos pacientes

CONTEXT AND OBJECTIVE: Hemoglobin (Hb) D hemoglobinopathies are widespread diseases in northwestern India and usually present with mild hemolytic anemia and mild to moderate splenomegaly. The heterozygous form of Hb D is clinically silent, but coinheritance of Hb D with Hb S or beta-thalassemia produces clinically significant conditions like thalassemia intermedia of moderate severity. Under heterozygous conditions with coinheritance of alpha and beta-thalassemia, patients show a degree of clinical variability. Thus, our aim was to molecularly characterize the Hb D trait among individuals who were clinically symptomatic because of co-inheritance of alpha deletions or any beta-globin gene mutations. DESIGN AND SETTING: This was a cross-sectional study conducted in an autonomous tertiary-care hospital. METHODS: Complete blood count and red cell indices were measured using an automated cell analyzer. Quantitative assessment of hemoglobin Hb F, Hb A, Hb A2 and Hb D was performed by means of high performance liquid chromatography (HPLC). DNA extraction was done using the phenol-chloroform method. Molecular analyses on common alpha deletions and common beta mutations were done using the Gap polymerase chain reaction and Amplification Refractory Mutation System, respectively. RESULTS: We evaluated 30 patients and found clinical variation in the behavior of Hb D traits. In six patients, the Hb D traits were clinically symptomatic and behaved like those of thalassemia intermedia. Molecular characterization showed that three out of these six were IVS-1-5 positive. CONCLUSIONS: HPLC may not be the gold standard for diagnosing symptomatic Hb D Punjab traits. Hence, standard confirmation should include molecular studies.

CONTEXTO E OBJETIVO: Hemoglobinopatias da hemoglobina (Hb) D são doenças amplamente disseminadas no noroeste da Índia e geralmente se apresentam com anemia hemolítica leve e esplenomegalia leve a moderada. A forma heterozigótica de Hb D é clinicamente silenciosa, mas co-herança de Hb D com Hb S ou beta-talassemia produzem condições clinicamente significativas, como talassemia intermediária de gravidade moderada. Em condição heterozigótica com co-herança de alfa e beta-talassemia, pacientes mostram variabilidade clínica. Assim, nosso objetivo foi a caracterização molecular dos traços da Hb D em individuos clinicamente sintomáticos, devido à co-herança de deleções de alfa ou quaisquer mutações gênicas de beta-globina. TIPO DE ESTUDO E LOCAL: Estudo transversal; realizado em um hospital de cuidado terciário autônomo. MÉTODOS: Hemograma completo e índices de células vermelhas foram medidos pelo analisador automatizado de células. Avaliação quantitativa de hemoglobina Hb F, Hb A, Hb A2 e Hb D foi realizada por cromatografia líquida de alta eficiência. Extração de DNA foi feita pelo método de fenol-clorofórmio. Estudo molecular para deleções comuns de alfa e mutações comuns de beta foi feito por Gap-reação em cadeia da polimerase e amplificação refratária de mutação, respectivamente. RESULTADOS: Avaliamos 30 pacientes e verificamos variação clínica no comportamento dos traços da Hb D. Em seis pacientes, os traços da Hb D foram clinicamente sintomáticos e se comportavam como os de talassemia intermédia. A caracterização molecular mostrou que três desses seis pacientes eram IVS-1-5 positivos. CONCLUSÕES: HPLC pode não ser o padrão ouro para o diagnóstico de traços de Hb D Punjab sintomáticos. Assim, a confirmação padrão ouro deve incluir estudos moleculares.

Hemoglobin I-Philadelphia [alpha 16 (A14) LYS-->GLU] heterozygote among blood donors from Brazil

We describe a heterozygous case of Hb I-Philadelphia [alpha 16 (A14) LYS-->GLU] in a blood donor from the Acre State Blood Bank, in the Brazilian Amazon region. We confirmed the mutation by electrophoretic and chromatographic methods and by DNA sequencing. A literature search showed that this is the first description of this alpha globin mutant in a Brazilian Caucasian group. We also emphasize the importance of the hemoglobin study in blood donors for the purpose of the genetic counseling and quality assurance of the blood to be transfused. Screening tests for hemoglobin mutants are also important for gathering anthropological information about the Brazilian population.

Análise dos haplótipos do gene da betaS-globina no Ceará / Analysis of betaS-globin gene haplotypes in Ceará, Brazil

No presente trabalho abordam-se vários aspectos relacionados à natureza molecular da anemia falciforme (AF), desordem hematológica de caráter hereditário. A descoberta do polimorfismo do DNA no grupamento do gene betaS, originando diferentes haplótipos da doença, permitiu ampliar o conhecimento em torno da heterogeneidade clínica observada nos pacientes falcêmicos nas mais diversas regiões do mundo. Analisaram-se os diferentes haplótipos e seus parâmetros hematológicos, presentes em um grupo de 22 pacientes naturais e procedentes do estado do Ceará. A distribuição das freqüências dos haplótipos encontrados foi de 55,9 por cento para Benin; 41,2 por cento para República Centro-Africana (CAR); e de 2,9 por cento para o haplótipo Senegal. Esses dados, em comparação com os demais estudos realizados no Brasil, mostram associação entre os seus valores para um alfa de 5 por cento (p < 0,05). Os resultados obtidos possibilitam um entendimento mais completo da fisiopatologia desta doença e da sua complexidade clínica em nosso meio, bem como permitem um conhecimento mais amplo da AF em nosso país.

Hemoglobinas anormales y talasemias en la República Mexicana / Abnormal hemoglobins and thalassemias in Mexico

La información en México sobre las anormalidades estructurales y de síntesis de la hemoglobina es resultado de encuestas y del estudio de pacientes que sufren anemia hemolítica. En población indígena se han estudiado varios miles de personas y concluído que las hemoglobinas anormales se encuentran virtualmente ausentes en indígenas puros y que los hallazgos esporádicos de Hb S identificados entre ellos se deben a mezcla con africanos atraídos a México como esclavos durante la colonia. En población indígena se han identificado dos nuevas variantes: la Hb México y la Hb Chiapas. En las encuestas en población híbrida de diversas regiones del país destaca que en ciertas regiones de las costas occidental y oriental de la república, se observa una frecuencia variable de terocigotos de Hb S y que en algunas poblaciones se han encontrado prevalencias elevadas de portadores de Hb S, semejantes a las encontradas en algunas regiones de Africa. En 200 sujetos estudiados en una población de la costa del Golfo de México (Tamiahua, Veracruz) se identificaron 6 por ciento de heterocigotos de Hb S y 15 por ciento de portadores de talasemia beta. Esta asociación explica por qué se han encontrado varios heterocigotos dobles de Hb S y talasemia beta, en esa zona del país. En 12,154 adultos estudiados en población hospitalaria de Guadalajara y puebla, se encontraron otras variantes hemoglobínicas anormales como C, SC, Riyadh, Baltimore, Tarrant, Fannin-Lubbock y México. La encuesta de una comunidad de origen italiano vecina a la ciudad de Puebla, mostró 1.3 por ciento de portadores de talasemia beta, frecuencia similar a la observada en las regiones de Italia de donde provinieron los ancestros de los act7uales pobladores. Estudiando sujetos afectados de anemia hemolítica se han identificado Hb I-Filadelfia, Hb G-San José y Hb D-Los Angeles. Por lo que hace a talasemias y síndromes talasemicos, puede afirmarse que talasemia es la anormalidad más frecuente de la hemoglobina en la población seleccionada de la república mexicana. Una revisión efectuada en nuestro laboratorio mostró que el 75 por ciento de las anormalidades de la hemoglobina corresponden a sujetos heterocigoto para talasemia beta...

Programa de Prevencion de Anemia Falciforme (II). Evaluacion del Segumiento de Gestantes con Hemoglobinas Anormales / Programme for Prevention of Sickle Cell Anemia (II). Evaluation of the follow-up of pregnants with abnormal hemoglobins

Algunos aspectos del programa Cubano de Prevencion de Anemia Falciforme fueron analizados en Ciudad de La Habana durante 1992. Todas las gestantes detectadas con hemoglobinas anormales fueron citadas por telegrama para explicarles el significado del hallazgo. El 62,2 por ciento acudio con prontitud a la citacion. El 21,6 por ciento vino mas tardiamente y se requirieron otros mecanismos de comunicacion. El 16,2 por ciento no acudio. Todas las gestantes que asistieron, aceptaron recibir asesoramiento genetico y se hizo el seguimiento de los casos. El 47,6 por ciento concluyo el estudio del conyuge en tiempo util para optar por diagnostico prenatal. Los resultados muestran la necesidad de reducir la edad gestacional en que se determina el riesgo de la pareja. Ello seria posible mediante el pesquisaje en la primera consulta prenatal, metodos mas eficientes en comunicar con las gestantes positivas, y mas agilidad en la realizacion de los analisis y en informar los resultados

Hemoglobinas anormais: perfil estatístico em doadores de sangue do Centro de Hematologia e Hemoterapia de Minas Gerais / Haemoglobinophaties in capable and uncapable blood samples donors from the Centro de Hematologia e Hemoterapia de Minas Gerais

As autoras apresentam um estudo sobre a frequência de hemoglobinopatias em amostras de sangue de doadores aptos e inaptos do Centro de Hematologia e Hemoterapia de Minas Gerais. Foram observados percentuais de 4,7 porcento e 6,7 para doadores aptos e inaptos em relaçäo à frequência de hemoglobinopatias. Devido aos possíveis prejuízos causados por transfusäo de sangue com hemoglobinopatias e levando em consideraçäo a significativa frequência desta alteraçäo, as autoras sugerem a intruduçäo dos principais métodos de diagnóstico nos serviços de Hemoterapia

Hemoglobina H: identificacao laboratorial / Hemoglobine H: laboratorial identification

A doenca por hemoglobina H (Hb H) e uma forma de alfa talassemia, caracterizada por baixa sintese de cadeia alfa e alta concentracao de cadeia beta; consequentemente a este desequilibrio ha formacao de tetrameros de cadeia beta ('beta IND.4'). A Hb H e relativamente comum na Tailandia e Grecia. Casos isolados tem sido relatados em chineses, filipinos e malasianos, confirmando que esta hemoglobina e frequente no Extremo Oriente; no Oriente Proximo sao relatados casos de Cipriota-grego e Arabe-jordaniano. Italia, Espanha, Canada, Indonesia e outros paises sao citados por terem apresentado casos de individuos portadores desta anomalia; no Brasil, foram publicados relatos de Hb H em familias de origens italiana, chinesa e negra. Nos identificamos a Hb H atraves de eletroforese, instabilidade e seus corpusculos caracteristicos.

Hemoglobin Bart's in a Brazilian black population

Hemoglobin Bart's was measured spectrophotometrically after electrophoreis on cellulose acetate strips in cord blood from 320 full-term randomly selected black new borns from the University Hospital of Campinas, State of Säo Paulo, in the southeast of Brazil. Hb Bart's was detected in 38 of the 320 newborns (11.0%), with the levels presenting the following bimodal distribution: 10.3% of the infants in the 1-3.5% range and 1.6% in the 5-10% range. The data suggest that the frequency of alfa-talassemia gene in the Brazilian black population is individuals with Bart's Hb in the 5-10% range are usually alfa+ -talassemia homozygotes

Prevalência de hemoglobinopatias em amostras de proveniência diferenciada / Prevalence of hemoglobinopathies in samples from different origen

Os autores analisaram as prevalências de hemoglobinas anormais variantes e talassemias, em amostras de diferentes proveniências (escolares, crianças de creches, jovens do tiro de guerra, usuários de postos de saúde, e pessoas com anemia a esclarecer) das cidades de Araçatuba, Barretos e Säo José do Rio Preto, SP, Brasil. Os resultados mostraram que há diferenças de prevalências, com significância estatística, apenas no grupo composto por pacientes com anemia a esclarecer. Os autores sugerem alguns requisitos fundamentais para a escolha da populaçäo ideal para estudos de prevalências de hemoglobinopatias