Newborn Screening Practices for Beta-Thalassemia in the United States

Causes of Death and Mortality Trends in Individuals with Thalassemia in the United States, 1999-2020

Purpose

Our study aims to describe the mortality trends and disparities among individuals with thalassemia in the United States (US).

Patients and Methods

We used CDC WONDER database to calculate the age-adjusted mortality rates (AAMRs) per 1,000,000 individuals and used the Joinpoint Regression Program to measure the average annual percent change (AAPC). Subgroup evaluations were performed by sex, age, race, census region, and urbanization level.

Results

From 1999 to 2020, there were 2797 deaths relatd to thalassemia in the US. The AAMR of thalassemia-related death showed a decreasing trend from 0.50 (95% CI, 0.41-0.58) in 1999 to 0.48 (95% CI, 0.41-0.55) in 2020 with the AAPC of -1.42 (95% CI, -2.42, -0.42). Asians have the highest AAMR (1.34 [95% CI, 1.20-1.47]), followed by non-Hispanic Blacks (0.65 [95% CI, 0.59-0.71]), non-Hispanic Whites (0.32 [95% CI, 0.30-0.33]), and Hispanics (0.11 [95% CI, 0.08-0.14]). Cardiovascular disease remains the leading cause of death among individuals with thalassemia. The urban population has a higher AAMR than the rural population (0.43 [95% CI, 0.41-0.45] vs 0.29 [95% CI, 0.26-0.32]).

Conclusion

Our study calls for targeted interventions to address the racial and geographic disparities existed among individuals of thalassemia in the US.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Point-of-Care Diagnostic Test for Beta-Thalassemia

Hemoglobin (Hb) disorders are among the most common monogenic diseases affecting nearly 7% of the world population. Among various Hb disorders, approximately 1.5% of the world population carries β-thalassemia (β-Thal), affecting 40,000 newborns every year. Early screening and a timely diagnosis are essential for β-thalassemia patients for the prevention and management of later clinical complications. However, in Africa, Southern Europe, the Middle East, and Southeast Asia, where β-thalassemia is most prevalent, the diagnosis and screening for β-thalassemia are still challenging due to the cost and logistical burden of laboratory diagnostic tests. Here, we present Gazelle, which is a paper-based microchip electrophoresis platform that enables the first point-of-care diagnostic test for β-thalassemia. We evaluated the accuracy of Gazelle for the β-Thal screening across 372 subjects in the age range of 4-63 years at Apple Diagnostics lab in Mumbai, India. Additionally, 30 blood samples were prepared to mimic β-Thal intermediate and β-Thal major samples. Gazelle-detected levels of Hb A, Hb F, and Hb A2 demonstrated high levels of correlation with the results reported through laboratory gold standard high-performance liquid chromatography (HPLC), yielding a Pearson correlation coefficient = 0.99. This ability to obtain rapid and accurate results suggests that Gazelle may be suitable for the large-scale screening and diagnosis of β-Thal.

Epidemiology of clinically significant forms of alpha- and beta-thalassemia: A global map of evidence and gaps

This systematic literature review assessed the global prevalence and birth prevalence of clinically significant forms of alpha- and beta-thalassemia. Embase, MEDLINE, and the Cochrane Library were searched for observational studies published January 1, 2000, to September 21, 2021. Of 2093 unique records identified, 69 studies reported across 70 publications met eligibility criteria, including 6 records identified from bibliography searches. Thalassemia prevalence estimates varied across countries and even within countries. Across 23 population-based studies reporting clinically significant alpha-thalassemia (e.g., hemoglobin H disease and hemoglobin Bart's hydrops fetalis) and/or beta-thalassemia (beta-thalassemia intermedia, major, and/or hemoglobin E/beta-thalassemia), prevalence estimates per 100 000 people ranged from 0.2 in Spain (over 2014-2017) to 27.2 in Greece (2010-2015) for combined beta- plus alpha-thalassemia; from 0.03 in Spain (2014-2017) to 4.5 in Malaysia (2007-2018) for alpha-thalassemia; and from 0.2 in Spain (2014-2017) to 35.7 to 49.6 in Iraq (2003-2018) for beta-thalassemia. Overall, the estimated prevalence of thalassemia followed the predicted pattern of being higher in the Middle East, Asia, and Mediterranean than in Europe or North America. However, population-based prevalence estimates were not found for many countries, and there was heterogeneity in case definitions, diagnostic methodology, type of thalassemia reported, and details on transfusion requirements. Limited population-based birth prevalence data were found. Twenty-seven studies reported thalassemia prevalence from non-population-based samples. Results from such studies likely do not have countrywide generalizability as they tended to be from highly specific groups. To fully understand the global prevalence of thalassemia, up-to-date, population-based epidemiological data are needed for many countries.

Clinical Classification, Screening, and Diagnosis in Beta-Thalassemia and Hemoglobin E/Beta-Thalassemia

This article reviews the classification of beta-thalassemia syndromes, correlating clinical severity and genotype in the earlier classification, and broadening it recently based on clinical severity and transfusion status. The classification is dynamic, and individuals may progress from transfusion-independent to transfusion-dependent. Early and accurate diagnosis prevents delays in instituting treatment and comprehensive care, and precludes inappropriate and potentially harmful interventions. Screening can inform risk in an individual and subsequent generations when partners may be carriers as well. This article discusses the rationale for screening of the at-risk population. In the developed world, a more precise genetic diagnosis must be considered.

A reliable and high throughput HPLC-HRMS method for the rapid screening of β-thalassemia and hemoglobinopathy in dried blood spots

OBJECTIVES

Traditional methods for β-thalassemia screening usually rely on the structural integrity of hemoglobin (Hb), which can be affected by the hemolysis of red blood cells and Hb degradation. Here, we aim to develop a reliable and high throughput method for rapid detection of β-thalassemia using dried blood spots (DBS).

METHODS

Hb components were extracted from a disc (3.2 mm diameter) punched from the DBS samples and digested by trypsin to produce a series of Hb-specific peptides. An analytical system combining high-resolution mass spectrometry and high-performance liquid chromatography was used for biomarker selection. The selected marker peptides were used to calculate delta/beta (δ/β) and beta-mutated/beta (β_M/β) globin ratios for disease evaluation.

RESULTS

Totally, 699 patients and 629 normal individuals, aged 3 days to 89 years, were recruited for method construction. Method assessment showed both the inter-assay and intra-assay relative standard deviation values were less than 10.8%, and the limits of quantitation for the proteo-specific peptides were quite low (1.0-5.0 μg/L). No appreciable matrix effects or carryover rates were observed. The extraction recoveries ranged from 93.8 to 128.7%, and the method was shown to be stable even when the samples were stored for 24 days. Prospective applications of this method in 909 participants also indicated good performance with a sensitivity of 100% and a specificity of 99.6%.

CONCLUSIONS

We have developed a fast, high throughput and reliable method for screening of β-thalassemia and hemoglobinopathy in children and adults, which is expected to be used as a first-line screening assay.

Screening and diagnosis of hemoglobinopathies in Germany: Current state and future perspectives

This monocentric study conducted at the Pediatric and Adult Hemoglobinopathy Outpatient Units of the University Hospital of Essen summarizes the results of hemoglobinopathies diagnosed between August 2018 and September 2021, prior to the introduction of a general newborn screening (NBS) for SCD in Germany (October 2021). In total, 339 patients (pts.), 182 pediatric [50.5% males (92/182)] and 157 adult pts. [75.8% females (119/157)] were diagnosed by molecular analysis. The most common (parental) descent among affected pts. were the Middle Eastern and North African/Turkey (Turkey: 19.8%, Syria: 11.8%, and Iraq: 5.9%), and the sub-Saharan African region (21.3%). Median age at diagnosis in pediatric carriers [N = 157; 54.1% males (85/157)] was 6.2 yrs. (range 1 (months) mos.–17.8 yrs.) and 31 yrs. (range 18–65 yrs.) in adults [N = 53; 75.2% females (115/153)]. Median age at diagnosis of homozygous or compound-heterozygous disease in pediatric pts. (72% (18/25) females) was 3.7 yrs., range 4 mos.–17 yrs. (HbSS (N = 13): 2.5 yrs., range 5 mos.–7.8 yrs.; HbS/C disease (N = 5): 8 yrs., range 1–8 yrs.; homozygous/compound heterozygous β-thalassemia (N = 5): 8 yrs., range 3–13 yrs.), in contrast to HbH disease (N = 5): 18 yrs. (median), range 12–40 yrs. Hemoglobinopathies represent a relevant health problem in Germany due to immigration and late diagnosis of second/third generation migrants. SCD-NBS will accelerate diagnosis and might result in reduction of disease-associated morbidity. However, diagnosis of carriers and/or disease-states (i.e. thalassemic syndromes) in newly immigrated and undiagnosed patients will further be delayed. A first major step has been taken, but further steps are required.