Neonatal Screening For Hemoglobinopathies Research Articles

Haemoglobinopathies and other rare anemias in Spain: ten years of a nationwide registry (REHem-AR)

REHem-AR was created in 2013. The progressive implementation of neonatal screening for haemoglobinopathies in Spanish autonomous communities where the registry had not been implemented, as well as the addition of new centres during this period, has considerably increased the sample of patients covered. In this study, we update our previous publication in this area, after a follow-up of more than 5 years. An observational, descriptive, multicentre and ambispective study of adult and paediatric patients with haemoglobinopathies and rare anaemias registered in REHem was performed. The data are from a cross-sectional analysis performed on 1 June, 2023. The study population comprised 1,756 patients, of whom 1,317 had SCD, 214 had thalassaemia and 224 were diagnosed with another condition. Slightly more than one third of SCD patients (37%) were diagnosed based on neonatal bloodspot screening, and the mean age at diagnosis was 2.5 years; 71% of thalassaemia patients were diagnosed based on the presence of anaemia. Vaso-occlusive crisis and acute chest syndrome continue to be the most frequent complications in SCD. HSCT was performed in 83 patients with SCD and in 50 patients with thalassaemia. Since the previous publication, REHem-AR has grown in size by more than 500 cases. SCD and TM are less frequent in Spain than in other European countries, although the data show that rare anaemias are frequent within rare diseases. REHem-AR constitutes an important structure for following the natural history of rare anaemias and enables us to calculate investment needs for current and future treatments.

Comparative analysis of the role of isoelectric focusing and high-performance liquid chromatography in newborn screening in hemoglobinopathies

Introduction: Hemoglobinopathies are the common genetic disorders and are considered as the emerging health burden. To reduce the childhood and infant mortality and morbidity, early recognition by newborn screening and timely intervention is necessary. Objectives: The objectives of this study are to evaluate the prevalence of different hemoglobinopathies in the study population and to compare the efficacy of isoelectric focusing (IEF) and high-performance liquid chromatography (HPLC) tests in the neonatal screening for hemoglobinopathies. We have also assessed the predominant mutations for all ?-thalassemia variants. Materials and Methods: The prospective observational study was conducted in the Department of Pathology in collaboration with the Department of Neonatology over 1½ years including 4200 neonates. Both IEF and HPLC diagnoses were attempted and compared with recall HPLC and parent HPLC. DNA analysis was also done further confirmation in all thalassemia cases. Results: A total of 213 cases with 11 Hb variants were detected; among them, HbE trait was the most prevalent type. Overall sensitivity, specificity, and negative and positive predictive values were noted. The results of IEF were comparable with HPLC with a statistically significant measure of agreement of ?=0.928 between the two. DNA analysis of 37 ?-thalassemia variants revealed three common mutations, i.e., cd26 (G>A), IVS1-5 (G>C), and cd15 (G>A). Conclusion: In IEF, the hemoglobin separation is very precise with little band overlap, but the process and interpretation need a high expertise. Due to more sensitivity, IEF should be the initial screening test followed by recall HPLC for confirmation of the diagnosis.

Hemoglobin variants identified in the Uganda Sickle Surveillance Study

AbstractThe Uganda Sickle Surveillance Study analyzed dried blood spots that were collected from almost 100 000 infants and young children from all 10 regions and 112 districts in the Republic of Uganda, with the primary objective of determining the prevalence of sickle cell trait and disease. An overall prevalence of 13.3% sickle cell trait and 0.7% sickle cell disease was recently reported. The isoelectric focusing electrophoresis technique coincidentally revealed numerous hemoglobin (Hb) variants (defined as an electrophoresis band that was not Hb A, Hb F, Hb S, or Hb C) with an overall country-wide prevalence of 0.5%, but with considerable geographic variability, being highest in the northwest regions and districts. To elucidate these Hb variants, the original isoelectric focusing (IEF) gels were reviewed to identify and locate the variant samples; corresponding dried blood spots were retrieved for further testing. Subsequent DNA-based investigation of 5 predominant isoelectric focusing patterns identified 2 α-globin variants (Hb Stanleyville II, Asn78Lys; Hb G-Pest, Asp74Asn), 1 β-globin variant (Hb O-Arab, Glu121Lys), and 2 fusion globin variants (Hb P-Nilotic, β31-δ50; Hb Kenya, Aγ81Leu-β86Ala). Compound heterozygotes containing an Hb variant plus Hb S were also identified, including both Hb S/O-Arab and HbS/Kenya. Regional differences in the types and prevalence of these hemoglobin variants likely reflect tribal ancestries and migration patterns. Algorithms are proposed to characterize these Hb variants, which will be helpful for emerging neonatal hemoglobinopathy screening programs that are under way in sub-Saharan Africa.

Neonatal screening program for hemoglobinopathies in the city of São Carlos, state of São Paulo, Brazil: analysis of a series of cases

ObjectiveTo analyze the neonatal screening program for hemoglobinopathies in São Carlos, Southeast Brazil, by investigating a series of cases in which the screening test was abnormal. More specifically, it was aimed to know the information regarding the neonatal screening received by mothers at the hospital and at primary health care, in addition to information related to genetic counseling. MethodsA descriptive study that enrolled 119 mothers, accounting for 73% of all children born between 2010 and 2011 with abnormal results of neonatal screening for hemoglobinopathies. The mothers completed a questionnaire that assessed the information received at hospital and primary health care, and issues related to genetic counseling. Descriptive statistics was performed. ResultsOf the 119 participating mothers, 69 (58%) had children with sickle cell trait, 22 (18.5%) with hemoglobin C trait, 18 (15.1%) with alpha thalassemia trait and, in 10 cases (8.4%), the result was inconclusive. At the hospital, 118 mothers (99.2%) received information about where to go to collect the test and 115 (96.6%) were informed about the correct time to collect the test. Only 4 mothers (3.4%) were informed about which diseases are investigated and the risks of not performing the screening. Seventeen mothers (14.3%) recognized the difference between trait and disease, and 42 (35.3%) considered that a positive screening test could have implications for future pregnancies. In 70 cases (58.8%), the child's physician was not informed about the screening test results. ConclusionsThe neonatal screening program needs further improvement. In both scenarios investigated, health professionals demonstrated a lack of training in providing information to mothers and families.

Triagem neonatal de hemoglobinopatias no município de São Carlos, São Paulo, Brasil: análise de uma série de casos

ObjectiveTo analyze the neonatal screening program for hemoglobinopathies in Sao Carlos, Sotheast Brazil, by investigating a series of cases which the screening test was abnormal. More specifically, it was aimed to know the information regarding the neonatal screening received by mothers at hospital and at primary health care, in addition to information related to genetic counseling. MethodsA descriptive study that enrolled 119 mothers, accounting for 73% of all children born between 2010 and 2011 with abnormal results of neonatal screening for hemoglobinopathies. The mothers completed a questionnaire that assessed the information received at hospital and primary health care, and issues related to genetic counseling. Descriptive statistics was performed. ResultsAmong the 119 participating mothers, 69 (58%) had children with sickle cell trait, 22 (18.5%) with hemoglobin C trait, 18 (15.1%) with alpha thalassemia trait and, in 10 cases (8.4%), the result was inconclusive. At hospital, 118 mothers (99.2%) received information about where to go to collect the test and 115 (96.6%) were oriented about the correct time to collect the test. Only 4 mothers (3.4%) were informed about which diseases are investigated and the risks of not performing the screening. Seventeen mothers (14.3%) recognized the difference between trait and disease, and 42 (35.3%) considered that a positive screening test could have implications for future pregnancies. In 70 cases (58.8%), the child physician was not informed about the screening test results. ConclusionsThe neonatal screening program need further improvement. In both scenarios investigated, health professionals demonstrated a lack of training in guiding mothers and families.

Neonatal screening for sickle cell disease and other hemoglobinopathies in "the changing Europe".

Inherited hemoglobin disorders (sickle-cell disorders and thalassaemias) represent an increasing global health problem. The early detection of sickle cell disease allows counselling for family members about disease management and future reproductive decisions. The aim of the present study was to estimate the birth prevalence of hemoglobinopathies in newborns of Italian couples and couples of immigrants from endemic areas living in an urban area of northern Italy in order to assess the opportunity of implementing a neonatal screening programme for hemoglobin disorders. Inclusion criteria were infants with at least one of the parents from high risk areas of hemoglobinopathies (Po delta and Sardinia, Italy; Mediterranean area; sub-Saharan Africa; Brazil; Asia) or a positive family history for hemoglobinopathies. The number of infants included in the present study was 337: 13.8% out of 2447 children born at Azienda Ospedaliera Universitaria (AOU) "Maggiore della Carità", Novara, Italy, from 31 December 2012 to 31 January 2014 and 47.6% of 710 infants with at least one foreign parent. 232 infants were wild-type (68.8%) for hemoglobin variants; 48 subjects (14.2%) had no hemoglobin variants, but we could not exclude the presence of a thalassemia trait (Hb A < 15%): a further monitoring of hemoglobin electrophoresis at 6 months was therefore recommended. 20 infants (5.9%) had Hb S (7.7% ± 3 of the total hemoglobin; range 3.5 - 13) and were diagnosed as Hb S carriers and 2 infants (0.6%) had Hb C (7.8% and 12.1% of the total hemoglobin, respectively) and were diagnosed as Hb C carriers. Based on our results, we can conclude that: (i) the sickle-cell disorder (Hb S) is relatively high in our territory, with a heterozygous frequency in infants at risk of 5.9%; (ii) the neonatal screening for hemoglobin disorders appears to be a valid, easy to perform test, which allows an early diagnosis and timely payment of hemoglobinopathies in populations at risk.

Diagnostic utility of isoelectric focusing and high performance liquid chromatography in neonatal cord blood screening for thalassemia and non-sickling hemoglobinopathies

BackgroundThalassemia syndromes are highly prevalent in Southeast Asia. In Thailand, high performance liquid chromatography (HPLC) is the most common technique routinely performed in diagnosis of thalassemia and hemoglobinopathies, while isoelectric focusing (IEF) is rarely employed. We compared the diagnostic utility of IEF and HPLC in neonatal screening for thalassemia and non-sickling hemoglobinopathies. MethodsTwo-hundred and forty-one cord blood samples were analyzed using IEF and HPLC, β-thalassemia short program. The results were correlated with red cell indices and molecular analyses. Hemoglobin (Hb) Bart's was quantified only on IEF. ResultsOf 241 newborns, IEF and HPLC yielded 85.4% and 76.4% sensitivity to identify α-thalassemia syndrome, respectively. HbBart's≥2% yielded 100% sensitivity to identify 2 α-globin gene deletions and/or mutations, while MCV≤95fl and MCH≤30pg yielded 100% sensitivity to identify 2 α-globin gene deletions. DNA analysis revealed HbE mutation in all 61 subjects with HbA2>1% on both IEF and HPLC. ConclusionIEF is an effective method in neonatal screening for thalassemia and non-sickling hemoglobinopathies. The HbBart's level, MCV and MCH are helpful for identifying α-thalassemia. The presence of HbA2 higher than 1% in cord blood indicates HbE carriers in Southeast Asian newborns.

Universal neonatal screening for sickle cell disease and other haemoglobinopathies in Ferrara, Italy.

Sickle cell disease is the commonest haemoglobinopathy in Africa, the Middle East and India. In recent years, its incidence has increased dramatically also in Europe and North America because of the high rate of migration of people from endemic areas. From January 2009 to January 2010 the number of foreign residents in the province of Ferrara (Italy) increased by 12.2%: most of the immigrants were from countries at high risk of sickle cell disease. Since neonatal screening and prophylactic penicillin in early childhood could reduce mortality by 10 years of age to less than 2%, the aim of this study was to establish a neonatal screening programme for haemoglobinopathies in Ferrara. First we assessed how many pregnant women underwent haemoglobin analysis by high performance liquid chromatography before or during pregnancy and how many of them were carriers of haemoglobinopathies. Subsequently, we verified the feasibility of neonatal screening for sickle cell disease and other haemoglobinopathies, analysing cord blood by high performance liquid chromatography. Neonates found to be positive were managed by a multidisciplinary team to implement all the appropriate prophylactic and therapeutic measures. We found that 59% of women who delivered at the University Hospital of Ferrara, from 2007 to 2009, had undergone high performance liquid chromatography. Of the 41% who were not tested, many were from areas in which sickle cell disease is common. Between September 26th 2010 and January 31st 2012, 1992 neonatal tests were performed and 24 carriers of haemoglobinopathies were identified (16 with HbS, 4 with HbC, 2 with HbE, 1 with HbD Punjab and 1 with HbD-Ouled Rabah); 42.6% of the mothers of these 1,992 neonates had not undergone high performance liquid chromatography during pregnancy. Currently prevention of haemoglobinopathies in Italy is provided during the pre-conception period but only to patients with abnormal blood counts. Neonatal screening is useful and cost-effective to ensure early diagnosis and appropriate treatment for infants with sickle cell disease or other haemoglobinopathies.

Screening for haemoglobinopathies on cord blood: laboratory and clinical experience

Blood from the umbilical cord (cord blood) is screened for haemoglobinopathies in several neonatal screening programmes, as well as before banking as a source of stem cells. We investigated the pre-analytical and analytical aspects of neonatal screening for haemoglobinopathies on liquid cord blood using the Sebia Haemoglobin kit. We give an interpretation of the results as well as a proposed scheme for reporting of the results. A neonatal screening programme on liquid cord blood has been performed in all labour wards in Brussels since 1994. Using that material, the screening methods of isoelectric focusing and capillary zone electrophoresis were compared using 962 cord blood samples. From December 2008 to December 2010, 47,388 neonatal samples were analysed by capillary electrophoresis as the first-line method for neonatal screening. High-performance liquid chromatography was used as the second-line method. Capillary zone electrophoresis on liquid cord blood enabled the detection of all clinically significant haemoglobin variants, significant levels of Hb Bart's, and β-thalassaemia major. Among the 47,388 neonatal samples tested, 362 (0.7%) were suspected to be contaminated with maternal blood, but no diagnostic error was reported retrospectively for a major haemoglobinopathy. Recommendations for the interpretation and reporting of results of neonatal screening for haemoglobinopathies using the Sebia Haemoglobin kit are proposed. A routine capillary electrophoresis kit adapted to neonatal screening and liquid cord blood is reliable for screening for haemoglobinopathies. It enables early detection and reporting of all major haemoglobinopathies and most minor ones. It also enables use of a simple scheme to report the results.

Diagnostic Challenge Presented by “Hb F only” Pattern In Newborn Screening for Hemoglobinopathies: Approach to Accurate Diagnosis

AbstractAbstract 5173Newborn screening for hemoglobinopathies has been proven to be an effective means of early diagnosis of clinically significant hemoglobinopathies such as sickle cell syndromes with early recruitment to clinical care and resultant reduction in morbidity and mortality. Neonatal screening for hemoglobinopathies is currently performed in 50 states utilizing screening methods such as hemoglobin electrophoresis or isoelectric focusing (IEF) complemented by High Performance Liquid Chromatography (HPLC) in a large number of states. These two methods yield accurate diagnosis of hemoglobinopathies especially of sickle cell disease in the vast majority of cases, although occasionally additional diagnostic approaches such as DNA based tests may be required for precise genetic diagnosis. One of the diagnostic challenges in newborn screening for hemoglobinopathies is posed by the observation of “Hb F only” pattern in electrophoresis/IEF and HPLC. This pattern can result from a spectrum of inherited globin gene abnormalities including homozygous β0 thalassemia, homozygous δβ-thalassemia, homozygous deletional HPFH (Hereditary Persistence of Fetal Hemoglobin), or a compound heterozygosity for any two of the above abnormalities. Since the clinical phenotype is dependent upon the underlying molecular defect, accurate diagnosis of the genotype in “Hb F only” cases is crucial in predicting the clinical course and planning therapy. The clinical spectrum of “Hb F only” (100% Hb F) cases in newborn screening ranges from severe transfusion dependent homozygous β0 thalassemia to completely asymptomatic homozygous deletional HPFH with intermediate phenotypes due to compound heterozygosity for any two of the above mentioned abnormalities. The prediction of the clinical phenotype based on the genotype is therefore important in ascertaining the significance of “Hb F only” cases. We present two cases of “F-only” phenotype detected during newborn screening, which were found to result from two distinct genotypes. Case 1 was an 8 mo old African-American male born in Sinai Hospital of Baltimore, MD at 39 weeks of gestation who was found to have 100% Hb F during newborn screening. He was referred to Pediatric Hematology at Sinai Hospital at two months of age, at which time a Hb electrophoresis confirmed the presence of 100% Hb F. His CBC showed a Hb of 13 g/dl, Hct 39%, RBC 4.68, MCV 84 fl, retic count 2.9%. At 8 months, he continued to be asymptomatic. She had a follow-up visit at 20 months of age and had Hbg 11.7, MCV 62; no repeat electrophoresis at that time. Work-up at MCG Sickle Cell Center Laboratory confirmed 100% Hb F with normal Hb and Hct. A gap PCR with primers specific for HPFH-1 and HPFH-2 deletions showed that the patient was a compound heterozygote for these two deletions. These findings were confirmed with family studies, which showed that the father was heterozygous for the HPFH-1 deletion, and the mother was heterozygous for HPFH-2. Case 2 was an African-American female born at UNC Hospital in Chapel Hill, NC. Newborn screening showed 100% Hb F. At age 2, she had a Hb of 11 g/dl, Hct 31.3%, MCV 80 fl. Hb analyses by HPLC revealed 96.2% Hb F, 2.9% Hb A, 0.9% Hb A2. Molecular analyses showed that the patient was a compound heterozygote for the HPFH-1 deletion and the β-globin promoter mutation, -90 C→T. These results were confirmed with family studies, which revealed that the father carried the HPFH-1 deletion while the mother was heterozygous for the rare -90 C→T mutation in the β-globin promoter. These two cases serve to illustrate the importance of detailed molecular diagnostic work up for the definite diagnosis of the genotype in “Hb F only” or 100% Hb F cases identified during neonatal screening for hemoglobinopathies. Since the phenotype of “100% Hb F” in a newborn can result from a variety of genotypes with a wide ranging spectrum of phenotypic expression, accurate genetic diagnosis is crucial in predicting the clinical course and determining the appropriate course of action. A stepwise approach to the work-up and the use of a combination of sensitive methods such as IEF, HPLC, and gene analysis will be helpful in establishing the correct diagnosis. Disclosures:No relevant conflicts of interest to declare.

Neonatal Screening for Hemoglobinopathies: Results of a Public Health System in South Brazil

The aim of this study was to estimate the prevalence of hemoglobinopathies in South Brazil. Samples of dried blood spots collected by heel prick in neonates were evaluated by isoeletric focusing and/or high-performance liquid chromatography techniques. All variants were characterized at the molecular level. A total of 437,787 samples were evaluated. Among these, 6391 showed an abnormal hemoglobin pattern. These included 48 cases (0.01%) of sickle cell disorders (33 hemoglobin SS [Hb SS], 7 Hb SC, 7 Hb S/beta thalassemia, 1 Hb SD), 1 neonate who was homozygous for beta thalassemia, 6272 (1.4%) newborns who were heterozygous for Hb S, C, or D, and 71 (0.02%) neonates who were carriers for rare hemoglobin variants. Most of these rare variants were identified for the first time in Brazil. Comparing these results with those obtained in other Brazilian regions, we observe a highly heterogeneous distribution. This knowledge is useful in healthcare planning and allocation of resources, as well as identifying at-risk couples, which will assist with disease prevention.

Implementing Neonatal Screening for Haemoglobinopathies in the Netherlands

The birth prevalence of severe haemoglobinopathies such as sickle cell disease (SCD) in the Netherlands has been estimated to be at least 50 newborns per year. Neonatal screening for SCD was added to the Dutch screening programme in January 2007. We here evaluated three high performance liquid chromatography (HPLC) systems for application in neonatal screening for haemoglobinopathies, and present the results of a subsequent pilot screening programme. The Variant NewBorn Screening (Vnbs) HPLC system (Bio-Rad) was validated by analysing 131 blood samples and blood mixtures. Subsequently, the performance of the G7 (Tosoh BioScience) and Ultra (Primus Corporation) was compared with the Vnbs. The three HPLC analysers were tested in a pilot screening programme on 21,969 dried blood spot samples from the routine Dutch neonatal screening programme. The pilot screening resulted in 188 abnormal patterns. The three HPLC devices presented comparable within- and between-run precision and detected the abnormal samples similarly. The high throughput, sampling systems, presentation of results, and integration of the chromatograms, however, were different. All three analysers detected the same abnormal haemoglobins satisfactorily, but integrated the chromatograms with variable imprecision. Comparison of the results suggested that the Bio-Rad Vnbs was the preferred system. However, software adjustments were required to improve the diagnostic potential of this device for screening for beta- and alpha-thalassaemia.

Management of transfusional iron overload in Latin America: current outlook and expert panel recommendations

The results of a meeting of physicians convening in Latin America to develop expert opinions on the diagnosis, monitoring and treatment of iron overload are as follows. An accurate diagnosis can be obtained by neonatal screening for haemoglobinopathies, especially sickle cell disease and the thalassaemias. Disease-specific registries are needed to demonstrate the extent of the problem to health authorities. Disparities in the quantity and quality of blood products must be addressed, and uniform transfusion guidelines are necessary. Serum ferritin level is a feasible marker for iron overload in the region, while magnetic resonance imaging assessment can improve the diagnosis and monitoring of cardiac and liver iron content. Medical specialists, including radiologists, pathologists and others, and health authorities, can help to implement these methods and provide adequate resources. The recently available oral deferasirox can be used to conveniently administer iron chelation to transfusional iron-overloaded patients.

Starting neonatal screening for haemoglobinopathies in The Netherlands

Neonatal screening for haemoglobinopathies started in The Netherlands on 1 January 2007. The method of choice, high-performance liquid chromatography, and the universal setting have shown that the predicted incidence is...

Neonatal haemoglobinopathy screening in Belgium

Background:A neonatal haemoglobinopathy screening programme was implemented in Brussels more than a decade ago and in Liège 5 years ago; the programme was adapted to the local situation.Methods:Neonatal screening for...

Neonatal haemoglobinopathy screening in Spain

The prevalence of variant haemoglobins in Spain is increasing as a result of recent African immigration. Of the 19 regions of Spain, 13 have more than 1% of residents of...

Neonatal/newborn haemoglobinopathy screening in Europe and Africa

Neonatal/newborn haemoglobinopathy screening is being performed in an increasing number of European countries since changing patterns of immigration have led to significant numbers of neonates at risk of sickle cell...

Relevance of α-Globin Genotyping in Patients Expressing HbH in Cord Blood: Prevalence of α-Globin Gene Deletions and α2-Globin Termination Codon Mutations in a Neonatal Hemoglobinopathy Screening Program

Introduction: α-Thalassemia results from an heterogeneous group of disorders involving the α-Globin genes. Common deletions are responsible for 95% of cases of α-thalassemia, whereas Constant Spring mutation (Hb CS), one of the known mutations involving the termination codon of α2-globin gene, is the most common non-deletional cause of α-thalassemia worldwide. Its prevalence has never been studied in occidental countries.Patients and methods: as part of our neonatal hemoglobinopathy screening program, fetal cord blood samples are systematically tested by HPLC. When an abnormal Hb or HbH is found, α-Globin deletion is carried by multiplex-PCR. A two part observational study was done at our center based on the available data from our hemoglobinopathy screening program available since 2002. Firstly, we aimed to determine the level of Hb H present and to correlate it to a specific type of α-Globin gene deletion by m-PCR sequencing (table 1). 306 samples were analyzed and demonstrated a statistically significant difference between categories of α-globin gene deletions: 2 del cis vs 1 del, 2 del trans vs 1 del, 2 del cis vs 2 del trans (difference of means of 8.07, 4.33 and 3.75 respectively, P<0.001). With HbH ≤3.15% a CI of 95% excludes a condition other that 1 α -globin gene deletion. With Hb H ≤7.1%, a CI of 99% excludes 2 α -globin gene deletions in cis.Table 1Deletion/allelic distributionHb H level (range)Hb H level (means)Std Dev1 deletion1.0 – 12.42.031.122 deletions cis-10.12.162 deletions trans-6.351.5Our second goal was to establish the prevalence of α-Globin termination codon mutation in the fetal blood sampling containing ≥1% of Hb H in absence of α-Globin gene deletion by m-PCR. 395 fetal blood samples were analysed. Of these, 59 lacked α-Globin gene deletions. 17 were excluded from our analysis for lack of personal data or DNA. The 42 remaining samples were studied by amplification of the termination codon followed by an enzymatic digestion for the recognition site TTAA. 2 samples (5%) were found to be heterozygotes for α2-globin mutation, presumably CS mutation. The small number of positive cases does not permit the conduct of a powerful statistical analysis, however the two mutated samples had a high level of Hb H (2,9%) whereas only 21% of the 42 studied samples had an Hb H ≥2%.Conclusion: These results represent a step forward in diagnosis of α-thalassemia and in identification of patients requiring particular genetic counselling based on HbH level at birth in cord blood. These results also indicate that 5% of Hb H positive/α-Globin deletion negative samples were caused by termination codon mutation in an occidental urban based population, and that it could be of interest to search for these mutations, especially when the Hb H level is high.

Ocorrência de hemoglobina S no estado de Mato Grosso do Sul, Brasil

INTRODUÇÃO: As hemoglobinopatias são as alterações genéticas mais comuns no homem, sendo a hemoglobina (Hb) S a mais freqüente entre todas. Sua ocorrência no estado de Mato Grosso do Sul ainda não foi sistematicamente avaliada. OBJETIVOS: Caracterizar a ocorrência de Hb S por genótipos, sexo, idade no momento do diagnóstico, índice de cobertura e prevalência em Mato Grosso do Sul. MATERIAL E MÉTODO: Estudo retrospectivo, transversal e descritivo, desenvolvido com os resultados de triagem neonatal para hemoglobinopatias, utilizando a técnica de cromatografia líquida de alta pressão, no Instituto de Pesquisas, Ensino e Diagnósticos da Associação de Pais e Amigos dos Excepcionais (IPED/APAE) de Mato Grosso do Sul em 2000-2005. RESULTADOS: De 190.809 indivíduos triados, 2.624 (1,38%) encontraram-se alterados, correspondendo a 2.385 neonatos e 239 crianças maiores de 28 dias. Não houve diferença entre os sexos, sendo 1.335 do sexo feminino e 1.289 do masculino. Os genótipos alterados encontrados foram traço falciforme (FAS [99,16%]) e doenças falciformes (FS [0,61%] e FSC [0,23%]). CONCLUSÃO: Esse primeiro estudo de triagem realizado no estado de Mato Grosso do Sul mostra que o programa desenvolvido pelo IPED/APAE está se solidificando no estado e avançando em relação ao índice de cobertura da população e ao diagnóstico precoce. Esses indicadores podem embasar ações preventivas (aconselhamento genético e estudos familiares) e assistenciais (tratamento ambulatorial contínuo), que visam à redução da morbimortalidade de indivíduos acometidos por essas afecções no estado.

Neonatal screening for haemoglobin variants using filter paper-dried blood specimens

Neonatal screening for haemoglobinopathies utilizing cord blood samples is well established, although it has a high miss rate and has the inherent problem of possible misdiagnosis from maternal contamination of the sample. The use of dried Guthrie card samples which are taken at six days of age avoids these problems and has the advantage of using an established system of sample collection. Controversy exists as to the method of choice for analysis of dried samples, this study of 2406 samples found that Iso-electric focusing (IEF) analysis of dried specimens gives excellent correlation when compared with cellulose acetate/citrate agar electrophoresis of liquid cord blood samples. The IEF results were clear and relatively simple to interpret even when the samples had been stored at room temperature for 4 weeks. The commercial enzyme linked immunosorbent assay (ELISA) screening test JOSHUA reliably determines the presence or absence of haemoglobin S in dried specimens. It could therefore be used as a relatively cheap and simple method for the confirmation of sickle cell trait in neonatal screening programmes based on dried specimens.