Comprehensive analysis of thalassemia alleles (CATSA) based on third-generation sequencing is a comprehensive and accurate approach for neonatal thalassemia screening

Thalassemia is one of the most common and damaging monogenic diseases in the world. It is caused by pathogenic variants of α- and/or β-globin genes, which disrupt the balance of these two protein chains and leads to α-thalassemia or β-thalassemia, respectively. Patients with α-thalassemia or β-thalassemia could exhibit a severe phenotype, with no simple and effective treatment. A three-tiered strategy of carrier screening, prenatal diagnosis and newborn screening has been established in China for the prevention and control of thalassemia, of which the first two parts have been studied thoroughly. The implementation of neonatal thalassemia screening is lagging, and the effectiveness of various screening programs has not yet been demonstrated. In this study, hemoglobin capillary electrophoresis (CE), hotspot testing method, and third-generation sequencing (TGS) were used in the variant detection of 2000 newborn samples, to assess the efficacy of these methods in neonatal thalassemia screening. Compared with CE (249, 12.45 %) and hotspot analysis (424, 21.2 %), CATSA detected the largest number of thalassemia variants (535, 26.75 %), which included 24 hotspot variants, increased copy number of α-globin gene, rare pathogenic variants, and three unreported potentially disease-causing variants. More importantly, CATSA directly determined the cis-trans relationship of variants in three newborns, which greatly shortens the clinical diagnosis time of thalassemia. CATSA showed a great advantage over other genetic tests and could become the most powerful technical support for the three-tiered prevention and control strategy of thalassemia.

Discovery of a biomarker for β-Thalassemia by HPLC-MS and improvement from Proton Transfer Reaction - Parallel Ion Parking

β-thalassemia is a quantitative hemoglobin (Hb) disorder resulting in reduced production of Hb A and increased levels of Hb A₂. Diagnosis of β-thalassemia can be problematic when combined with other structural Hb variants, so that the separation approaches in routine clinical centers are not sufficiently decisive to obtain accurate results. Here, we separate the intact Hb subunits by high-performance liquid chromatography, followed by top-down tandem mass spectrometry of intact subunits to distinguish Hb variants. Proton transfer reaction-parallel ion parking (PTR-PIP), in which a radical anion removes protons from multiply charged precursor ions and produces charge-reduced ions spanning a limited m/z range, was used to increase the signal-to-noise ratio of the subunits of interest. We demonstrate that the δ/β ratio can act as a biomarker to identify β-thalassemia in normal electrospray ionization MS1 and PTR-PIP MS1. The application of PTR-PIP significantly increases the sensitivity and specificity of the HPLC-MS method to identify δ/β ratio as a thalassemia biomarker.

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.

Neutral-Coating Capillary Electrophoresis Coupled with High-Resolution Mass Spectrometry for Top-Down Identification of Hemoglobin Variants

BACKGROUND

Identification of hemoglobin (Hb) variants is of significant value in the clinical diagnosis of hemoglobinopathy. However, conventional methods for identification of Hb variants in clinical laboratories can be inadequate due to the lack of structural characterization. We describe the use of neutral-coating capillary electrophoresis coupled with high-resolution mass spectrometry (CE-HR-MS) to achieve high-performance top-down identification of Hb variants.

METHODS

An Orbitrap Q-Exactive Plus mass spectrometer was coupled with an ECE-001 capillary electrophoresis (CE) unit through an EMASS-II ion source. A PS1 neutral-coating capillary was used for CE. Samples of red blood cells were lysed in water and diluted in 10 mM ammonium formate buffer for analysis. Deconvolution of raw mass spectrometry data was carried out to merge multiple charge states and isotopic peaks of an analyte to obtain its monoisotopic mass.

RESULTS

The neutral-coating CE could baseline separate individual Hb subunits dissociated from intact Hb forms, and the HR-MS could achieve both intact-protein analysis and top-down analysis of analytes. A number of patient samples that contain Hb subunit variants were analyzed, and the variants were successfully identified using the CE-HR-MS method.

CONCLUSIONS

The CE-HR-MS method has been demonstrated as a useful tool for top-down identification of Hb variants. With the ability to characterize the primary structures of Hb subunits, the CE-HR-MS method has significant advantages to complement or partially replace the conventional methods for the identification of Hb variants.

Mass spectrometry in the clinical laboratory. A short journey through the contribution to the scientific literature by CCLM

Mass spectrometry (MS) has been a gold standard in the clinical laboratory for decades. Although historically refined to limited areas of study such as neonatal screening and steroid analysis, technological advancements in the field have resulted in MS becoming more powerful, versatile, and user-friendly than ever before. As such, the potential for the technique in clinical chemistry has exploded. The past two decades have seen advancements in biomarker detection for disease diagnostics, new methods for protein measurement, improved methodologies for reliable therapeutic drug monitoring, and novel technologies for automation and high throughput. Throughout this time, Clinical Chemistry and Laboratory Medicine has embraced the rapidly developing field of mass spectrometry, endeavoring to highlight the latest techniques and applications that have the potential to revolutionize clinical testing. This mini review will highlight a selection of these critical contributions to the field.

Advances in mass spectrometric methods for detection of hemoglobin disorders

Hemoglobin disorders are caused due to alterations in the hemoglobin molecules. These disorders are categorized in two broad classes - hemoglobin variants and thalassemias. The hemoglobin variants arise due to point mutations in the alpha (α), beta (β), gamma (γ), delta (δ), or epsilon (ε) globin chains of these proteins, while thalassemias are caused due to the under-production of α or β globin chain. Hemoglobin disorders account for 7 % of the major health issues globally. Mass Spectrometry is an extensively used analytical tool in the field of protein identification, protein-protein interaction, biomarker discovery and diagnosis of several impairments including hemoglobin related disorders. The remarkable advancements in the technology and method development have enormously augmented the clinical significance of mass spectrometry in these fields. The present review describes hemoglobin disorders and the recent advancements in mass spectrometry in the detection of such disorders, including its advantages, lacunae, and future directions. The literature evidence concludes that mass spectrometry can be potentially used as a 'First Line Screening Assay' for the detection of hemoglobin disorders in the near future.

A Novel Dried Blood Spot Detection Strategy for Characterizing Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in China. Conventional diagnostic methods are dependent on advanced instruments, which are expensive, inaccessible, and inconvenient in underdeveloped areas. To build a novel dried blood spot (DBS) detection strategy for imaging CVDs, in this study, a total of 12 compounds, including seven amino acids [homocysteine (Hcy), isoleucine (Ile), leucine (Leu), valine (Val), phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp)], three amino acid derivatives [choline, betaine, and trimethylamine N-oxide (TMAO)], L-carnitine, and creatinine, were screened for their ability to identify CVD. A rapid and reliable method was established for the quantitative analysis of the 12 compounds in DBS. A total of 526 CVD patients and 200 healthy volunteers in five provinces of China were recruited and divided into the following groups: stroke, coronary heart disease, diabetes, and high blood pressure. The orthogonal projection to latent structures-discriminant analysis (OPLSDA) model was used to characterize the difference between each CVD group. Marked differences between the groups based on the OPLSDA model were observed. Based on the model, the patients in the three training sets were mostly accurately categorized into the appropriate group. In addition, the receiver operating characteristic (ROC) curves and logistic regression of each metabolite chosen by the OPLSDA model had an excellent predictive value in both the test and validation groups. DBS detection of 12 biomarkers was sensitive and powerful for characterizing different types of CVD. Such differentiation may reduce unnecessary invasive coronary angiography, enhance predictive value, and complement current diagnostic methods.

Analytical Chemistry in the 21st Century: Challenges, Solutions, and Future Perspectives of Complex Matrices Quantitative Analyses in Biological/Clinical Field

Nowadays, the challenges in analytical chemistry, and mostly in quantitative analysis, include the development and validation of new materials, strategies and procedures to meet the growing need for rapid, sensitive, selective and green methods. In this context, considering the constantly updated International Guidelines, constant innovation is mandatory both in the pre-treatment procedures and in the instrumental configurations to obtain reliable, true, and reproducible information. In this context, additionally to the classic plasma (or serum) matrices, biopsies, whole blood, and urine have seen an increase in the works that also consider non-conventional matrices. Obviously, all these studies have shown that there is a correlation between the blood levels and those found in the new matrix, in order to be able to correlate and compare the results in a robust way and reduce any bias problems. This review provides an update of the most recent developments currently in use in the sample pre-treatment and instrument configurations in the biological/clinical fields. Furthermore, the review concludes with a series of considerations regarding the role and future developments of Analytical Chemistry in light of the forthcoming challenges and new goals to be achieved.