Newborn screening for hemoglobinopathies in California

Prevalence of hemoglobin S trait among blood donors: a cross-sectional study

Background

Sickle cell trait (SCT) or Hemoglobin S (HbS) trait which is due to inheritance of an abnormal hemoglobin (Hb) gene from one parent and a normal gene from the other has been known to be common among people of African descent. Individuals with SCT may find themselves in the blood donor population without knowing their ‘carrier’ status and this may have severe consequences on their health as well as that of a recipient, particularly if they happen to be a sickle cell disease patient. The aim of the study was to determine the prevalence of HbS trait among blood donors.

Results

This cross-sectional study employed convenience sampling method to recruit subjects. A total of 150 prospective and healthy blood donors comprising 138 males and 12 females were involved in the study. Two (2) ml of venous blood was collected from each donor into K₃EDTA tubes and analyzed using the sodium metabisulphite slide test and cellulose acetate Hb electrophoresis at alkaline pH (8.6) for Hb genotypes. Statistical Package for Social Sciences version 20.0 (SPSS 20.0) and Chi square were used to analyse the data obtained. Out of the 150 blood donors, 133 (88.7 %) tested negative for sickling (131 were genotype AA and 2 were AC) and 17 (11.3 %) tested positive for sickling, all of whom were genotype AS.

Conclusion

The results of the study showed the existence of SCT among the blood donor population sampled. Taking blood from such people can harm their health as well as that of the recipient if they happen to be sickle cell disease (SCD) patients. It is therefore recommended that blood donors as well as donated blood units should be screened for SCT to avoid causing any harm to both the donor and recipient.

Pulmonary Embolism and Infarct After Bilateral Cochlear Implantation in a Patient with Newly Diagnosed Sickle/β+ Thalassemia

OBJECTIVE

To heighten awareness of increased postoperative thromboembolic complications in patients with β-hemoglobinopathies.

PATIENT

A 42-year-old African American woman with previously undiagnosed β-hemoglobinopathies suffers from sensorineural hearing loss caused by bacterial meningitis and undergoes bilateral cochlear implantation.

INTERVENTION(S)

Diagnostic: hemoglobin electrophoresis. Therapeutic: cochlear implantation, anticoagulation.

MAIN OUTCOME MEASURE(S)

Risk of thromboembolic event.

RESULTS

Five days after surgery, the patient developed pulmonary embolism and infarct in the right lower lobe, which was treated with a 4-month course of anticoagulation. Hemoglobin electrophoresis showed that the patient had a previously undiagnosed rare β-hemoglobinopathy known as sickle/β+ thalassemia.

CONCLUSION

β-Hemoglobinopathies are associated with a higher incidence of thromboembolism; thus, they should be managed aggressively to prevent or treat perioperative thrombosis.

An international effort to cure a global health problem: A report on the 19th Hemoglobin Switching Conference

Every 2 years since 1978, an international group of scientists, physicians, and other researchers meet to discuss the latest developments in the underlying etiology, mechanisms of action, and developmental acquisition of cellular and systemic defects exhibited and elicited by the most common inherited human disorders, the hemoglobinopathies. The 19th Hemoglobin Switching Conference, held in September 2014 at St. John's College in Oxford, once again exceeded all expectations by describing cutting edge research in cellular, molecular, developmental, and genomic advances focused on these diseases. The conference comprised about 60 short talks over 3 days by leading investigators in the field. This meeting report describes the highlights of the conference.

Sickle cell in Latin America and the United States [corrected]

Latin Americans are an underappreciated population affected by sickle cell disease (SCD). Sickle trait and SCD exist throughout Latin America and U.S. Latino communities. We describe the epidemiology and genetic heterogeneity of SCD among Latin Americans, and fetal hemoglobin expression. National population-based newborn screening for SCD is limited to Brazil, Costa Rica, and the U.S. Available and extrapolated data suggest that over 6,000 annual births and 100,000-150,000 Latin Americans are affected by SCD. This comprehensive review highlights the substantial numbers and population distribution of SCD and sickle trait in Latin America, and where national newborn screening programs for SCD exist.

α-Globin as a molecular target in the treatment of β-thalassemia

The thalassemias, together with sickle cell anemia and its variants, are the world's most common form of inherited anemia, and in economically undeveloped countries, they still account for tens of thousands of premature deaths every year. In developed countries, treatment of thalassemia is also still far from ideal, requiring lifelong transfusion or allogeneic bone marrow transplantation. Clinical and molecular genetic studies over the course of the last 50 years have demonstrated how coinheritance of modifier genes, which alter the balance of α-like and β-like globin gene expression, may transform severe, transfusion-dependent thalassemia into relatively mild forms of anemia. Most attention has been paid to pathways that increase γ-globin expression, and hence the production of fetal hemoglobin. Here we review the evidence that reduction of α-globin expression may provide an equally plausible approach to ameliorating clinically severe forms of β-thalassemia, and in particular, the very common subgroup of patients with hemoglobin E β-thalassemia that makes up approximately half of all patients born each year with severe β-thalassemia.

Evaluation of hemoglobin A1c measurement by Capillarys 2 electrophoresis for detection of abnormal glucose tolerance in African immigrants to the United States

BACKGROUND

Hemoglobin A1c (HbA1c) is used to monitor long-term glycemic control in individuals with diabetes, guide therapy, predict the risk of microvascular complications, and more recently to diagnose diabetes. An automated liquid-flow capillary electrophoresis method was recently developed to measure HbA1c using the Capillarys 2 Flex Piercing instrument.

METHODS

Analytical evaluation was performed at 2 clinical centers. A clinical analysis was conducted in 109 African-born individuals, 24% of whom have variant hemoglobin (HbAS or HbAC). Abnormal glucose tolerance (which includes both diabetes and prediabetes) was defined as 2h glucose of ≥ 140 mg/dl (7.8 mmol/l) during an oral glucose tolerance test.

RESULTS

Interlaboratory CVs were ≤ 2.1%. The method showed satisfactory correlation with 2 other analyzers that measure HbA1c by high-performance liquid chromatography. Neither labile HbA1c, carbamylated hemoglobin, uremia, bilirubin nor common hemoglobin variants (HbC/HbS/HbE) interfered. Forty-five individuals (41%) had abnormal glucose tolerance. The sensitivity of HbA1c for diagnosing abnormal glucose tolerance was 38%, 36% and 42% for total, normal and variant hemoglobin groups, respectively.

CONCLUSIONS

The analytical performance of HbA1c on the Capillarys 2 is suitable for clinical application. Variant hemoglobin in Africans did not interfere with the detection of abnormal glucose tolerance by HbA1c measured on the Capillarys 2.

Increasing prevalence of thalassemia in America: Implications for primary care

Thalassemia, once a rarity in the United States, is increasingly encountered in clinical practice due to shifts in immigration. Early carrier screening in at-risk populations can help clinicians implement genetic counseling and prevent new cases. Chronic transfusions are the mainstay of therapy for patients with severe thalassemia (beta thalassemia major), and are used intermittently in individuals with milder forms of thalassemia (Hb H/H Constant Spring disease and beta thalassemia intermedia). Iron overload is a major source of morbidity and mortality in individuals with transfusion and non-transfusion-dependent thalassemia, necessitating iron chelation therapy. Iron overload contributes to increased risk of cirrhosis, heart failure, and endocrinopathies, while ineffective erythropoiesis and hemolysis contribute to multiple complications, including splenomegaly, extramedullary hematopoiesis, pulmonary hypertension, and thrombosis. An understanding of the importance of carrier screening, complications, monitoring, and management strategies, coupled with collaboration with a hematologist with thalassemia expertise, is essential to reduce the morbidity and mortality in patients with thalassemia.

When to consider transfusion therapy for patients with non-transfusion-dependent thalassaemia

Non-transfusion-dependent thalassaemia (NTDT) refers to all thalassaemia disease phenotypes that do not require regular blood transfusions for survival. Thalassaemia disorders were traditionally concentrated along the tropical belt stretching from sub-Saharan Africa through the Mediterranean region and the Middle East to South and South-East Asia, but global migration has led to increased incidence in North America and Northern Europe. Transfusionists may be familiar with β-thalassaemia major because of the lifelong transfusions needed by these patients. Although patients with NTDT do not require regular transfusions for survival, they may require transfusions in some instances such as pregnancy, infection or growth failure. The complications associated with NTDT can be severe if not properly managed, and many are directly related to chronic anaemia. Awareness of NTDT is important, and this review will outline the factors that should be taken into consideration when deciding whether to initiate and properly plan for transfusion therapy in these patients in terms of transfusion interval and duration of treatment.

Non-Transfusion Dependent Thalassemia: Translating Evidence to Guidelines

The thalassemias are a group of inherited disorders of hemoglobin synthesis characterized by various degrees of defective production of the α- or β-globin chains of adult hemoglobin A. Non-transfusion- dependent thalassemia (NTDT) includes a group of thalassemia patients who do not require regular RBC transfusions for survival, but may require occasional transfusions due to infection or pregnancy or may require more regular transfusions later in life due to splenomegaly or other complications. Due to the rising phenomenon of global migration, this previously well-localized entity is currently spreading more and more worldwide reaching Northern America and Northern Europe. The clinical picture of NTDT is governed by the severity of the ineffective erythropoiesis and the chronic hemolytic anemia, which, in turn, lead to iron overload, hypercoagulability, and an array of clinical complications involving almost every organ system. Patients with NTDT suffer from complications that are distinct from those encountered in patients with transfusion- dependent thalassemia (TDT) in addition to the complications shared by both TDT and NTDT. As a consequence, patients with NTDT deserve a care specifically tailored to their needs. In the care of patients with NTDT, aiming at a standardized yet personalized care is not an easy task especially that NTDT patients lie on a heterogeneous spectrum with a wide variability in their clinical presentation and response to therapy. Therefore, guidelines emerge as a necessity to answer the specific needs of NTDT patients and the clinicians caring for them. In this article, we summarize the complications most commonly associated with NTDT and the recommendations of the guidelines for the management of patients with NTDT, based on the best available evidence.

Feasibility of a newborn screening and follow-up programme for sickle cell disease among South Gujarat (India) tribal populations

OBJECTIVES

To evaluate the feasibility of a newborn screening and follow-up programme for sickle cell disease (SCD) among tribal populations of south Gujarat, India.

METHODS

A total of 5467 newborn babies were screened over 2 years using High-performance liquid chromatography, with diagnosis by molecular analysis. The SCD babies were followed-up clinically and haematologically regularly for 1.5 to 5 years to describe the course of the disease.

RESULTS

Thirty-three babies (0.60%) were sickle homozygous, 13 (0.23%) were-sickle-β-thalassaemia, 687 (12.5%) were sickle heterozygous, and 4736 were unaffected. The parents of SCD babies were educated and counselled for home care. There were 32 babies (69.5%) who could be clinically and haematologically followed-up; 7 babies (21.8%) presented with severe clinical complications, whereas 18 (56.2%) babies were asymptomatic till the last follow-up. The variation in clinical presentation was seen in spite of the presence of ameliorating factors, such as high fetal haemoglobin, Xmn-I polymorphism, and α-thalassaemia.

CONCLUSION

In addition to demonstrating the possibility of establishing a newborn screening programme for sickle cell disorders among tribal populations, this study has shown that the disease is not always mild among tribal groups in India, as previously believed. There is a need, therefore, for increasing awareness among these tribal groups about the disease, and for regular monitoring of affected babies to reduce morbidity and mortality and to understand the natural course of the disease.

Advances in technologies for screening and diagnosis of hemoglobinopathies

Hemoglobinopathies constitute the most common monogenic disorders worldwide, caused by mutations in the globin genes that synthesize the globin chains of hemoglobin. Synthesis may be reduced (thalassemia) or underlie abnormal hemoglobins. Mutation interactions produce a wide range of disorders. For neonatal and antenatal screening, identification of affected newborns or carriers is achieved by hematological tests. DNA analysis supports definitive diagnosis, and additionally facilitates prenatal diagnosis procedures. Most methods used today have been developed over several decades, with few recent advances in hematology methods. However, DNA methods evolve continuously. With global migration and multiethnic societies the trend is from targeted, population-specific methods towards generic methods, such as Sanger sequencing (point mutations) and multiplex ligation probe amplification (deletions). DNA microarrays constitute an advanced DNA method for some mutation categories. The newest DNA technology is next-generation sequencing. Although not completely ready for routine use currently, next-generation sequencing may soon become a reality for some hemoglobin diagnostic laboratories.

Newborn screening program for hemoglobinopathies in Rio de Janeiro, Brazil

BACKGROUND

Newborn screening for hemoglobinopathy in Brazil has been decentralized until 2001 when the Health Ministry of Brazil established the National Newborn Hemoglobinopathy Screening Program. The State of Rio de Janeiro started a program in collaboration with the State Health Department and the Institute of Hematology in Rio (HEMORIO). The goal of this study was to evaluate the effectiveness of the first 10 years of the Newborn Hemoglobinopathy Screening Program in identifying and managing infants with Sickle cell disease (SCD) in the State of Rio de Janeiro.

PROCEDURE

Blood samples from 1,217,833 neonates were analyzed by High Performance Liquid Chromatography. Infants with SCD were enrolled in comprehensive treatment programs.

RESULTS

Data showed that 4.87% of the newborns were heterozygous for a hemoglobin variant, 0.08% were homozygous or doubly heterozygous for abnormal hemoglobins and 95.02% had normal hemoglobin. All the 912 newborns with SCD were referred for treatment at HEMORIO, 34 (3.7%) of these died due to acute chest syndrome, sepsis or splenic sequestration. Four more children died of unknown causes. The implementation of the Rio de Janeiro Newborn Screening Program gradually increased the area of the State covered by the program.

CONCLUSION

Data collected during the 10 years of the program showed reduction in mortality of patients with SCD in comparison to available historical statistical data before the implementation of the national screening program. This 10-year study showed that early diagnosis and treatment of newborns was associated with improved survival and quality of life of Brazilian children with SCD.

Identifying sickle cell disease cases using administrative claims

OBJECTIVE

To develop and test the accuracy of administrative claims method for identifying children with sickle cell disease (SCD) to enable quality of care assessments among children enrolled in Medicaid.

METHODS

All administrative claims with an SCD diagnosis were obtained from Michigan Medicaid from 2008 to 2011 for children ≤18 years, representing 1828 individuals. All Medicaid claims were obtained for these children and classified into categories on the basis of SCD care; these classifications were used to develop 37 alternative case definitions for identifying children with SCD. Children with ≥1 SCD claim in 2010 or 2011 were identified as confirmed SCD or not SCD using the gold standard of Michigan newborn screening administrative records. Measures of performance were calculated for each case definition for eligible children in 2010. Further validation of the case definitions was performed among eligible children in 2011.

RESULTS

In 2010, a total of 938 children met eligibility criteria and were linked to newborn screening records; 605 (59%) were confirmed SCD, and 333 (32%) were not SCD. Measures of performance varied among the 37 case definitions, and the 4 best case definitions on the basis of the sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve were validated among 924 children meeting eligibility criteria in 2011. The case definition of at least 3 SCD claims in any position identified children with SCD with the most accuracy, with an area under the ROC curve of 0.91 (95% confidence interval 0.89, 0.93).

CONCLUSIONS

This definition can be used to facilitate a more accurate identification of children with SCD in future studies. Further investigation is necessary to determine whether this method translates to other populations besides Michigan Medicaid-insured children.

Non-transfusion-dependent thalassemias

Non-transfusion-dependent thalassemias include a variety of phenotypes that, unlike patients with beta (β)-thalassemia major, do not require regular transfusion therapy for survival. The most commonly investigated forms are β-thalassemia intermedia, hemoglobin E/β-thalassemia, and α-thalassemia intermedia (hemoglobin H disease). However, transfusion-independence in such patients is not without side effects. Ineffective erythropoiesis and peripheral hemolysis, the hallmarks of disease process, lead to a variety of subsequent pathophysiologies including iron overload and hypercoagulability that ultimately lead to a number of serious clinical morbidities. Thus, prompt and accurate diagnosis of non-transfusion-dependent thalassemia is essential to ensure early intervention. Although several management options are currently available, the need to develop more novel therapeutics is justified by recent advances in our understanding of the mechanisms of disease. Such efforts require wide international collaboration, especially since non-transfusion-dependent thalassemias are no longer bound to low- and middle-income countries but have spread to large multiethnic cities in Europe and the Americas due to continued migration.

Newborn screening for Hb H disease by determination of Hb Bart's using the Sebia capillary electrophoresis system in southern China

Hb H (β4) disease is an inherited hemoglobin (Hb) defect in which three of the four α-globin genes are deleted or dysfunctional. The clinical manifestations vary widely from mild asymptomatic anemia to a severely anemic state. Recent literature suggests that Hb H disease is not as benign a disorder as previously thought. Newborn screening for Hb H disease is especially appealing because the screening test is based on the detection of Hb Bart's (γ4) that is only possible within the newborn period. In a 2-year period of newborn screening, 18 babies were found to have Hb H disease in a total of 9490 newborns. The overall prevalence for Hb H disease among all newborns in southern China is approximately 1 in 500. The correct diagnosis would allow affected infants to be properly cared for and reduce mortality rate.

Deferasirox for the treatment of iron overload in non-transfusion-dependent thalassemia

Non-transfusion-dependent thalassemia (NTDT) defines a group of patients who do not require regular transfusions for survival, but are at significant risk of iron accumulation from underlying disease-related mechanisms distinct from transfusional iron overload. Management of iron overload in NTDT has received little attention compared with that of β-thalassemia major, despite evidence of significant iron-induced complications with advancing age. The efficacy and safety of the iron chelator deferasirox in NTDT has been evaluated in two pilot studies and the first prospective, randomized, placebo-controlled study (THALASSA) of any chelator in NTDT. Treatment with deferasirox for up to 2 years yielded a sustained reduction in iron burden, with a clinically manageable safety profile. Following these trial data, deferasirox is the first iron chelator approved for use in NTDT patients, and with NTDT guidelines now available, physicians are better equipped to achieve effective monitoring and management of iron burden in NTDT.

Clinical manifestations of α-thalassemia

α-Thalassemia mutations affect up to 5% of the world's population. The clinical spectrum ranges from an asymptomatic condition to a fatal in utero disease. Hemoglobin H disease results from mutations of three α-globin genes. Deletional forms result in a relatively mild anemia, whereas nondeletional mutations result in a moderate to severe disease characterized by ineffective erythropoiesis, recurrent transfusions, and growth delay. Hemosiderosis develops secondary to increased iron absorption, as well as transfusion burden. Hemoglobin Bart's hydrops fetalis is usually a fatal in utero disease caused by the absence of α genes. Population screening to identify at-risk couples is essential. Affected pregnancies result in severe fetal and maternal complications. Doppler ultrasonography with intrauterine transfusion therapy may improve the fetal prognosis but creates ethical challenges for the family and health providers.

Treating iron overload in patients with non-transfusion-dependent thalassemia

Despite receiving no or only occasional blood transfusions, patients with non-transfusion-dependent thalassemia (NTDT) have increased intestinal iron absorption and can accumulate iron to levels comparable with transfusion-dependent patients. This iron accumulation occurs more slowly in NTDT patients compared to transfusion-dependent thalassemia patients, and complications do not arise until later in life. It remains crucial for these patients' health to monitor and appropriately treat their iron burden. Based on recent data, including a randomized clinical trial on iron chelation in NTDT, a simple iron chelation treatment algorithm is presented to assist physicians with monitoring iron burden and initiating chelation therapy in this group of patients. Am. J. Hematol. 88:409–415, 2013. © 2013 Wiley Periodicals, Inc.

Sickle-Cell Trait and Atopic and Inflammatory Disease in Children

Roughly 9% of African-Americans carry 1 copy of the sickle β-globin allele [sickle-cell trait (SCT)]. The sickle allele may affect the host responses in a way that protects against sequelae of malaria. Besides the association with sporadic episodes of erythrocyte sickling, acute chest syndrome, and sudden death, the SCT is generally regarded as asymptomatic. Separately, and for unclear reasons, the African-Americans have an elevated risk compared to whites for several immune-mediated diseases, including asthma, eczema, and other respiratory conditions. We propose to determine whether the SCT contributes to the elevated risk of these inflammatory conditions. We performed a retrospective cohort study of children with and without the sickle trait to assess the risk for common immune-mediated conditions. The cohorts were individually matched, and multiple logistic regression was used with variables selected using a backward stepwise approach. A second approach (case-control design) assessed the odds of the SCT among African-Americans with and without asthma. We found 2,481 children with and 4,962 matched patients without the SCT in the cohort design. The sickle trait was associated with greater odds for several immune-mediated conditions in a multivariable analysis, but not associated with asthma (odds ratio, OR=1.10, P=0.212). In an adjusted case-control analysis (n=20,000), the sickle trait was weakly associated with asthma [adjusted odds ratio (aOR)=1.46, 1.01-2.13]. In both the designs and in all statistical models used, we found that the SCT was associated with bronchitis (aOR=1.71, 1.09-2.67) and eczema (aOR=1.74, 1.23-2.46). The SCT may contribute to an increased risk for eczema and asthma-like symptoms in the African-American children.

Newborn screening for hemoglobinopathies using capillary electrophoresis

This chapter reports the essential elements needed to understand basic laboratory diagnostics consisting of separation and measurement of the hemoglobin fractions. Although well established, basic diagnostics require some background and some degree of experience for application and interpretation. Last generation methods, consisting of automatic systems like high performance liquid chromatography and capillary electrophoresis (CE), allow high through put analysis in adults and newborns. Newborn screening using CE is presented in some details, using as an example the Capillarysâ Neonat Hb system (Sebia, France), as an upcoming alternative, explaining the method, the interpretation of the results, the objectives, the follow up, the advantages, and the pitfalls.

Effectiveness of preoperative screening for sickle cell disease in a population with a newborn screening program: a cohort study

PURPOSE

Published clinical practice guidelines recommend that all patients from ethnic groups with a high prevalence of sickle cell disease (SCD) undergo preoperative screening for this hemoglobinopathy. Newborn Screening Ontario initiated a universal sickle hemoglobinopathy screening program in 2006 as part of its regional newborn screening program. The primary objective of this study was to determine the effectiveness of selective preoperative screening for SCD based on at-risk ethnicity in Ontario, a region that has a universal newborn sickle hemoglobinopathy screening program.

METHODS

The hematology laboratory database at our hospital was searched to identify all children who underwent preoperative sickle cell screening in the 42-month period starting in November 2006 (when the newborn sickle hemoglobinopathy screening program was introduced) and ending in April 2010. Medical records of all children testing positive on hemoglobin analysis were reviewed to determine perioperative outcomes.

RESULTS

Our search strategy identified 710 children who were born after the introduction of newborn screening and who underwent preoperative screening. Thirty-five of these children had abnormal sickle solubility tests - one (0.14%) was a new diagnosis (not identified by newborn screening), one had been diagnosed previously, and 33 (4.65%) were identified as having sickle cell trait. Sixty children had more than one preoperative screening test performed (range, 2-4). Six of the 35 children with abnormal sickle solubility results underwent repeated testing.

CONCLUSIONS

Preoperative screening based on at-risk ethnicity alone is an ineffective method of identifying additional children with SCD in Ontario, a population with universal newborn sickle hemoglobinopathy screening. In an effort to avoid unnecessary repeat testing, we propose an algorithm to help physicians decide whether to initiate preoperative sickle cell screening for children.

Screening for haemoglobinopathies on cord blood: laboratory and clinical experience

Objectives

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.

Methods

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.

Results

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.

Conclusions

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.

Advances in the treatment of alpha-thalassemia

Alpha (α)-thalassemia represents a group of recessively inherited hemoglobin disorders marked by deficient or absent synthesis of 1 to all 4 of the α-globin genes. Inactivation of 3 α-globin genes--either by deletional or nondeletional mutations--results in hemoglobin H (Hb H) disease. Patients with Hb H disease produce hemoglobin composed of all beta chains and have moderate to severe hemolytic anemia, a variable degree of ineffective erythropoiesis, and splenomegaly. Transfusion requirements vary depending on the mutation and clinical severity. Treatment for deletional Hb H disease is primarily preventative and transfusions are uncommon. Patients with nondeletional Hb H disease (e.g., Hb H Constant Spring) typically have more severe anemia, and approximately one-third require regular transfusions. These patients often require comprehensive, multidisciplinary care. This chapter focuses on screening, diagnosis, and treatment approaches for patients with Hb H disease.

Exploring Family Communication About Sickle Cell Disease in Adolescence

Sickle cell disease (SCD) is a lifelong disorder that involves progressive organ damage and requires ongoing medical attention to prevent and treat episodic acute complications. Children with SCD need ongoing monitoring and extra attention that may be stressful to family members. Communication within families can help resolve family stress and may be associated with medical follow-up and management of SCD. Focus groups were conducted with 12 African American families to explore the communication that occurred within and outside of the family from the perspectives of adolescents with SCD, siblings, and parents. Factors that influence family communication were explored. The extended family was an important social network and resource to adolescents, siblings, and parents. Family member knowledge of SCD was an important factor that influenced communication about SCD; adolescents and parents communicated more easily than siblings and also reported having more knowledge of SCD than siblings. Future research focusing on the knowledge of immediate and extended family members and their recognition of their contribution to the child with SCD is recommended.

Birth prevalence of disorders detectable through newborn screening by race/ethnicity

PURPOSE

The purpose of this study was to describe the birth prevalence of genetic disorders among different racial/ethnic groups through population-based newborn screening data.

METHODS

Between 7 July 2005 and 6 July 2010 newborns in California were screened for selected metabolic, endocrine, hemoglobin, and cystic fibrosis disorders using a blood sample collected via heel stick. The race and ethnicity of each newborn was self-reported by the mother at the time of specimen collection.

RESULTS

Of 2,282,138 newborns screened, the overall disorder detection rate was 1 in 500 births. The disorder with the highest prevalence among all groups was primary congenital hypothyroidism (1 in 1,706 births). Birth prevalence for specific disorders varied widely among different racial/ethnic groups.

CONCLUSION

The California newborn screening data offer a unique opportunity to explore the birth prevalence of many genetic disorders across a wide spectrum of racial/ethnicity classifications. The data demonstrate that racial/ethnic subgroups of the California newborn population have very different patterns of heritable disease expression. Determining the birth prevalence of these disorders in California is a first step to understanding the short- and long-term medical and treatment needs faced by affected communities, especially those groups that are impacted by more severe disorders.

Neonatal screening of sickle cell anemia: a preliminary report

OBJECTIVE

To evaluate feasibility of systematic neonatal screening for sickle cell disease in Chhattisgarh.

METHODS

A pilot study was done from February 2008 through January 2009 in Department of Pediatrics & Neonatology, Pt. J.N.M. Medical College & Dr.B.R.A.M. Hospital, Raipur (Chhattisgarh) on a total of 1,158 neonates. Blood samples from the neonates were taken after 48 h of birth on filter paper for detection of sickle cell anemia using Biorad hemoglobin variant Neonatal sickle cell short programme by high performance liquid chromatography (HPLC). On follow up, cases were analyzed by HPLC using Beta thalassemia short program to rule out false negative case and other hemoglobin variants.

RESULTS

Of the 1,158 neonates screened, 628 were boys (54.2%) and 530 were girls (45.8%). Sickle cell disease was found in 3 cases (0.2%) (95%C.I 0.12-0.28), sickle cell trait was found in 68 cases (5.8%) (95%C.I 4.5-7.5). After 6-9 mo of age three cases of sickle cell diseases were reinvestigated, out of which one case turned out to be double heterozygous for sickle cell and beta thalassemia trait. Fourteen preterm neonates reported as normal in initial screening were called for follow up after 6 mo of age, 10 infants reported in OPD and 4 lost in follow up. These 10 infants were reinvestigated; 2 had sickle cell disease, 1 had sickle cell trait and 7 infants were normal. Sixty eight cases of sickle cell trait found with initial screening were also called for follow up after 6 mo of age; 61 cases reported in OPD between 6 mo to 1 y of age and 7 cases lost in follow up. Sixty one infants were reinvestigated; 60 had sickle cell trait and 1 had sickle cell disease which was reported earlier as Sickle cell trait (FAS). Thus on total follow up of cases, there were 5(0.4%) sickle cell disease, 61(5.26%) sickle cell trait, 1(0.08%) double heterozygous for sickle cell and beta thalassemia trait which needs mutation studies for thalassemia characterization (s/β(0) or s/β(+)).

CONCLUSIONS

Early detection of sickle cell disease (SS) done by neonatal screening will help in early prevention and management of complications in postnatal period.

First case of Hb Fontainebleau with sickle haemoglobin and other non-deletional α gene variants identified in neonates during newborn screening for sickle cell disorders

OBJECTIVE

To evaluate the significance of non-deletional α gene variants identified in neonates during newborn screening for sickle cell disorders.

METHODS

1534 newborn babies were screened in the last 2 years for sickle cell disease using a targeted screening approach. Investigations included a complete blood count, high performance liquid chromatography analysis, cellulose acetate electrophoresis (pH 8.9), heat stability test, restriction digestion and Amplified Refractory Mutation System for confirmation of sickle haemoglobin (Hb S), α genotyping by multiplex PCR and DNA sequencing.

RESULTS

Three non-deletional α gene variants, Hb Fontainebleau, Hb O Indonesia and Hb Koya Dora, were identified in heterozygous condition in newborns. This is the first report of Hb Fontainebleau in association with Hb S. The baby had anaemia at birth (Hb 11.4 g/dl) with no cyanosis, icterus or need for transfusion. She had occipital encephalocoele and was operated on day 24 to remove the mass. The baby diagnosed with Hb O Indonesia in combination with Hb S also had a low haemoglobin level of 12.7 g/dl.

CONCLUSION

Newborn screening for sickle cell disorders also enabled us to identify three α globin chain variants. Two babies who inherited Hb Fontainebleau and Hb O Indonesia along with Hb S had reduced Hb levels at birth and need to be followed up.

A transgenic mouse model expressing exclusively human hemoglobin E: indications of a mild oxidative stress

Hemoglobin (Hb) E (β26 Glu→Lys) is the most common abnormal hemoglobin (Hb) variant in the world. Homozygotes for HbE are mildly thalassemic as a result of the alternate splice mutation and present with a benign clinical picture (microcytic and mildly anemic) with rare clinical symptoms. Given that the human red blood cell (RBC) contains both HbE and excess α-chains along with minor hemoglobins, the consequence of HbE alone on RBC pathophysiology has not been elucidated. This becomes critical for the highly morbid β(E)-thalassemia disease. We have generated transgenic mice exclusively expressing human HbE (HbEKO) that exhibit the known aberrant splicing of β(E) globin mRNA, but are essentially non-thalassemic as demonstrated by RBC α/β (human) globin chain synthesis. These mice exhibit hematological characteristics similar to presentations in human EE individuals: microcytic RBC with low MCV and MCH but normal MCHC; target RBC; mild anemia with low Hb, HCT and mildly elevated reticulocyte levels and decreased osmotic fragility, indicating altered RBC surface area to volume ratio. These alterations are correlated with a mild RBC oxidative stress indicated by enhanced membrane lipid peroxidation, elevated zinc protoporphyrin levels, and by small but significant changes in cardiac function. The C57 (background) mouse and full KO mouse models expressing HbE with the presence of HbS or HbA are used as controls. In select cases, the HbA full KO mouse model is compared but found to be limited due to its RBC thalassemic characteristics. Since the HbEKO mouse RBC lacks an abundance of excess α-chains that would approximate a mouse thalassemia (or a human thalassemia), the results indicate that the observed in vivo RBC mild oxidative stress arises, at least in part, from the molecular consequences of the HbE mutation.

Asthma morbidity and treatment in children with sickle cell disease

Children with sickle cell disease (SCD) and a comorbid condition of asthma have increased numbers of vaso-occlusive pain and acute chest syndrome episodes, and all-cause mortality. When assessed systematically, asthma prevalence is probably similar among children with SCD when compared with the general African-American population. With increasing recognition of the importance of asthma in the management of SCD, hematologists must become familiar with asthma and develop a multidisciplinary approach, including early recognition, appropriate management and referral to asthma specialists.

Sickle cell disease in California: sociodemographic predictors of emergency department utilization

BACKGROUND

Patients with sickle cell disease (SCD) visit emergency departments (EDs) in rates leading to a significant health system burden. However, limited comprehensive evaluations of utilization patterns have been published using data connecting visits to patients across facilities. This study aims to examine sociodemographic predictors of ED utilization in SCD.

PROCEDURE

This retrospective cohort study employed 2007 data from the California Office of Statewide Health Planning and Development (OSHPD). Data included all ED encounters from California hospitals; identifiers connected each visit to an individual patient, across all facilities in the state. Multivariate regression techniques evaluated sociodemographic predictors of utilization while adjusting for confounding variables.

RESULTS

In 2007, 2,920 California patients with SCD made 16,364 ED visits. Adults ≥ 21 years of age had higher ED visit rates than children and were more likely to both be in the highest tier of users and visit multiple facilities. Patients living further from a self-identified provider of comprehensive SCD care had higher rates of ED visits and a lower likelihood of hospitalization from the ED. Publicly insured patients had higher rates of ED visits and were more likely to be in the highest tier of users than were the privately insured or uninsured.

CONCLUSIONS

Adulthood ≥ 21 years of age, distance from comprehensive SCD care, and insurance status are significant predictors of ED utilization in SCD. As a routine source of care decreases ED utilization, these findings prompt concern that these factors act as barriers to accessing comprehensive SCD care.

Relationship between neonatal screening results by HPLC and the number of α-thalassaemia gene mutations; consequences for the cut-off value

Objectives

To evaluate the relationship between FAST peak percentage by adapted Bio-Rad Vnbs analysis using the valley-to-valley integration and genotypes with the aim to improve differentiation between severe α-thalassaemia forms (HbH disease) and the milder disease types.

Method

DNA analysis for α-thalassaemia was performed on 91 dried blood spot samples presenting normal and elevated FAST peak levels, selected during three years of Dutch national newborn screening.

Results

Significant differences were found between samples with and without α-thalassaemia mutations, regardless of the genetic profiles. No significant difference was demonstrated between HPLC in -α/αα and -α/-α, between -α/-α and –/αα and between –/αα and –/-α genotypes.

Conclusion

This study confirms that the percentage HbBart's, as depicted by the FAST peak, is only a relative indication for the number of α genes affected in α-thalassaemia. Based on the data obtained using the modified Bio-Rad Vnbs software, we adopted a cut-off value of 22.5% to discriminate between possible severe α-thalassaemia or HbH disease and other α-thalassaemia phenotypes. Retrospectively, if this cut-off value was utilized during this initial three-year period of neonatal screening, the positive predictive value would have been 0.030 instead of 0.014.

Increased prevalence of false positive hemoglobinopathy newborn screening in premature infants

BACKGROUND

The objective was to investigate the specificity of the hemoglobinopathy newborn screening in premature neonates as compared to term neonates.

PROCEDURE

The screening results from infants suspected to have hemoglobinopathy disease identified by the Florida Newborn Screening Program for years 2002-2007 were compared to the corresponding confirmatory testing. The risks for false positives for preterm and full term newborns were calculated by Chi-square or the Cochran-Armitage test for trend. Isoelectric focusing and HPLC were the methods of hemoglobin screening.

RESULTS

Over 2,300 neonates (1/576 neonates born in Florida) were suspected to have hemoglobinopathy. The most common abnormal pattern in term and preterm infants (gestational age 22-36 weeks) suggesting disease at screening was FS. Overall, 93% of the children who screened positive for FCA and 64% of infants identified with FSA were later confirmed with trait. FSC was confirmed in 96% of the cases in both preterm and term infants. Compared to term newborns, preterm newborns were more likely to have a false positive result for FS or FC at screening. Twenty-three percent of preterms with FS and 59% of preterms with FC were diagnosed as traits by confirmatory testing, compared to only 2% and 6% for term infants (P < 0.001).

CONCLUSIONS

As compared to term newborns, more preterm newborns with trait were misidentified as having sickle cell anemia or hemoglobin C at screening. We speculate that abnormal hemoglobins may precede the development of hemoglobin A during fetal life.

Feasibility of nonselective testing for hemoglobinopathies in early pregnancy in The Netherlands

OBJECTIVE

To examine the feasibility of standardized hemoglobinopathy (HBP) carrier testing for pregnant women in The Netherlands in addition to the standard anemia screening.

METHODS

We assessed the prevalence of HBP in women at the time of the first pregnancy visit using both a prospective cohort (N = 703) and a retrospective series of women selected at random (N = 588). For the purpose of analysis, the population was divided into a high risk and a low risk group for HBP based on maternal ethnicity. Screening for HBP utilized standard screening tests for anemia, with additional high performance liquid chromatography (Variant II); molecular analysis was performed by Gap-polymerase chain reaction (Gap-PCR) and if necessary, direct sequencing and multiplex ligation-dependent probe amplification (MLPA). Family history was reported or collected from the medical records.

RESULTS

β-Globin defects were found in 3.9% of the total population (50/1291). The frequency in the high risk population was 5.6% (37/656), compared with 1.2% (6/501) in the low risk group. In the prospective study we found 30 HBP carriers, leading to testing of 16 partners and identification of two couples at risk. One affected child was born. Mean gestational age at the screening was 11.3 weeks with a standard deviation (SD) of 5.8.

CONCLUSION

We found that the prevalence of HBP carriers is high enough in our population to warrant HBP testing for the entire multiethnic population in early pregnancy at the time of anemia screening. This is feasible as most women had their booking early in their first trimester.

Newborn screening for hemoglobin disorders

The epidemiology of hemoglobinopathies in the United States reflects recent changes in the demographic make-up of the country's population. The incidence of thalassemias, in particular, has risen in parallel with immigration of high-risk populations. With an increase in Asian immigration by 2000% in the past three decades, hemoglobinopathies such as Hb H (β4) and Hb E-β-thalassemia (β-thal) have acquired proportionally greater clinical significance in several states, including California. Newborn screening (NBS) for hemoglobinopathies allows for the identification of affected individuals so that prophylactic treatment and comprehensive care may be provided prior to the development of clinical complications. Although the more common hemoglobin (Hb) variants, such as Hb S or Hb C, are readily identified by NBS programs, other clinically significant Hb disorders often remain unresolved or are not reported by NBS programs. The state of California mandates NBS and follow-up for thalassemic disorders as well as sickle cell disease. A centralized laboratory for diagnostic testing and rapid reporting of NBS results is a necessary component of a comprehensive NBS program. Confirmatory diagnostic testing for the California NBS program is provided by the Hemoglobinopathy Reference Laboratory at Children's Hospital & Research Center Oakland (CHRCO), Oakland, CA, USA. Using electrophoresis, high performance liquid chromatography (HPLC) and DNA-based methods, the laboratory annually performs diagnostic testing for sickle cell disease, β-thal and Hb H disease on more than 1,000 samples. While most screening results are straightforward, 5% of newborns identified with a presumptive hemoglobinopathy by primary screening are modified after confirmatory testing. The availability of rapid and reliable genotyping assays to complement traditional protein chemistry methods for hemoglobinopathy screening has facilitated the diagnosis of thalassemias and sickling disorders in newborns with ambiguous screening results. Together with coordinated follow-up systems in place, the Hemoglobinopathy Reference Laboratory has contributed to the success of the NBS program in the rapid identification and delivery of care to newborns with clinically significant Hb disorders.

Weighing the evidence for newborn screening for Hemoglobin H disease

OBJECTIVE

To conduct a systematic review to assist the United States Secretary of Health and Human Services Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) to determine whether Hemoglobin H screening should be included among the core recommended conditions for newborn screening.

STUDY DESIGN

We identified 21 articles in MEDLINE from 1989 to March 2010 that provided evidence regarding screening, treatment, and outcomes associated with Hemoglobin H disease.

RESULTS

In California, newborn screening has identified 9 cases per 100 000 of deletional hemoglobin H disease and 0.6 cases per 100 000 of nondeletional hemoglobin H disease. Five cases of hemoglobin Bart's hydrops fetalis syndrome were also identified in over ten years of screening for Hemoglobin H disease. Although Hemoglobin H disease is associated with a wide range of morbidity, no studies were found that evaluated the benefits of early identification and treatment.

CONCLUSIONS

The SACHDNC found the data insufficient to recommend that states adopt newborn screening for Hemoglobin H disease.

Heterogeneity of hemoglobin H disease in childhood

BACKGROUND

Early diagnosis during newborn screening or infancy has enabled the observation of the natural history of hemoglobin H disease, a subtype of α-thalassemia.

METHODS

We analyzed longitudinal clinical data for patients with hemoglobin H disease arising from the deletion of three of four α-globin genes (HbH) and from hemoglobin H Constant Spring (HCS), caused by the deletion of two α-globin genes and the Constant Spring mutation.

RESULTS

We identified 86 patients with hemoglobin H disease (48 through newborn screening). Of these patients, 60 (70%) had HbH, 23 (27%) had HCS, and 3 (3%) had other, nondeletional forms of hemoglobin H disease. The parental ethnic background was Asian in 81% of patients, Hispanic in 5%, and African American in 3%, whereas mixed ancestry was observed in 10% of patients. Among the patients with deletional hemoglobin H disease, 15% had one or both parents with African-American ancestry. Growth was normal in patients with HbH during the first decade, but growth deficits began during infancy in those with HCS. Anemia was more severe in patients with HCS at all ages (P<0.001). Acute worsening of anemia with infections requiring urgent blood transfusion was observed in patients with HCS but not in those with HbH. The probability of receiving at least one transfusion by the age of 20 years was 3% for patients with HbH and 80% for those with HCS (P<0.001). Among patients with HCS, transfusions occurred in 13% of infants and 50% of children under the age of 6 years; splenectomy was associated with a significant improvement in hemoglobin levels (P=0.01) and a reduction in the number of transfusions.

CONCLUSIONS

HCS should be recognized as a distinct thalassemia syndrome with a high risk of life-threatening anemia during febrile illnesses. HbH was not associated with an increased rate of severe anemia with infections and was managed without blood transfusions. Many patients with these disorders had mixed ethnic backgrounds, which highlights the need for extended newborn screening in populations that are traditionally considered to be at low risk for hemoglobin H disease.

Neonatal screening for hemoglobinopathies: results of a public health system in South Brazil

AIM

The aim of this study was to estimate the prevalence of hemoglobinopathies in South Brazil.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Complexity of alpha thalassemia: growing health problem with new approaches to screening, diagnosis, and therapy

Alpha thalassemia, the most common genetic disorder of hemoglobin synthesis, affects up to 5% of the world's population. It represents a group of conditions with reduced or absent synthesis of one to all four of alpha globin genes. Deletional or nondeletional mutations occur on chromosome 16. Its severity ranges from asymptomatic to fatal in utero. Hemoglobin H disease, a mutation of three alpha globin genes, is more severe than previously recognized. Anemia, hypersplenism, hemosiderosis, growth failure, and osteoporosis are commonly noted as the patient ages. Alpha thalassemia major, a usually fatal in utero disease, is now recognized to have a complex molecular and phenotypic expression with increasing births being reported. Surviving newborns without intrauterine transfusion often have congenital anomalies and neurocognitive injury. Serious maternal complications often accompany pregnancy. Doppler ultrasonography with intrauterine transfusion ameliorates these complications. The high incidence in many populations mandates population screening and prenatal diagnosis of at-risk couples. Universal newborn screening has been adopted in several regions with DNA confirmatory testing. These advances have resulted in ethical dilemmas for the family and the provider.